JPH08340136A - Oxide thin film element manufacturing method, superconducting element manufacturing method and superconducting element - Google Patents

Abstract

(57) [Summary] [Problem] To provide a method for manufacturing an oxide thin film element, particularly a superconducting element, in which manufacturing efficiency is improved by reducing the number of lithography steps and deterioration of film characteristics due to the lithography steps is prevented. To do. [Structure] When a metal oxide compound and active oxygen are supplied to a substrate in a vacuum chamber to form an oxide thin film, the ratio of the molecule supply density of the organometallic compound to the active oxygen supply density on the substrate is Change spatially. As a result, in a single thin film layer, for example, an oxide thin film that has been epitaxially grown with good crystallinity, an oxide thin film that has poor crystallinity and is easily etched, or a conductive thin film that contains carbon at 10 at% or more, etc. Create multiple parts with different electrical properties and crystallinity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an oxide thin film element, a method for manufacturing a superconducting element and a superconducting element.

[0002]

2. Description of the Related Art In the process of manufacturing a superconducting element, a thin film having a buffer layer, an insulating layer, a resistance layer, a superconducting layer, etc. is laminated on a substrate. A step of patterning each thin film is required. For patterning, apply photoresist and expose /
It is performed by developing and removing unnecessary portions by wet etching, ion beam etching, or lift-off. It is also possible to perform patterning by ion beam etching using a metal mask.

FIG. 34 (S. Kosaka, in “Adva.
nces in Cryogenic Engineering Materials ”Volume 3
2, Edited by RPReed and AFClark, (Plenum press,
New York, 1986) pp.507-516). In the Josephson integrated circuit shown in FIG. 34, reference numeral 1 is a substrate, and a Josephson junction 4 is formed on the superconducting layer 2 serving as a ground plane formed on the substrate 1 with an interlayer insulating layer 3 interposed therebetween. Superconducting layers 5 and 6 and a resistance film 7 are formed. A Josephson integrated circuit using such a latch type logic requires as many resistors as the number of junctions. On the other hand, rapid single-flux-quantum (RSFQ)
Element (KK Likharev and V.K.Semenov, IEEE Trans. App
l.Supercond. vol.1, pp.3-28) also requires a resistor in the integrated circuit. The conventional manufacturing process will be described by taking the Josephson integrated circuit as an example. First, a superconducting layer 2 to be a ground plane is deposited on a substrate 1, and then an interlayer insulating layer 3 is deposited, and interlayer insulating is performed by photolithography and etching of a resist. Contact holes 8 are formed in the layer 3. Then, after depositing the resistance film 7, only the necessary portions of the resistance film 7 are left by photolithography, and the superconducting layers 5 and 6, the insulating layer 9 and the like are laminated and patterned. Further, since a groove is formed between the resistance film 7 and the adjacent superconducting layer 6 or between the insulating layer 9 and the adjacent superconducting layer 5, the groove is formed by a method such as spin-on-glass (SOG) 10. Fill and flatten. As described above, the conventional technique requires a large number of lithography steps and flattening steps.
Furthermore, when Nb, NbN, or the like is used as the superconducting layers 5 and 6, oxygen is diffused into the superconducting layers 5 and 6 at the portions in contact with the insulating layers 3 and 9 made of SiO or the like, and the superconducting characteristics are likely to deteriorate. There was a problem.

Further, a conventional example of a passive microwave element using an oxide superconductor is shown in FIG. A sapphire substrate 11 is used as a substrate, and a substrate 11 made of CeO ₂ or the like is formed thereon.
A buffer layer 13 for preventing a reaction between the superconducting layer 12 and the superconducting layer 12 is deposited, and the superconducting layer 12 is deposited thereon. Then, a strip line or a filter is formed by leaving only a necessary portion of the superconducting layer 12 by photolithography. In such a conventional passive microwave device, in the lithography process after depositing the superconducting layer 12,
There has been a problem that deterioration of characteristics such as the critical temperature T _c and surface resistance of the superconducting layer 12 cannot be avoided.

In a copper oxide superconductor, it is generally difficult to form a laminated Josephson junction having high characteristics. Therefore,
The bi-epitaxial Josephson junction has attracted attention because it has relatively good characteristics and can form the junction at any position on the substrate. FIG. 36 shows an example of the structure and manufacturing process of a conventional bi-epitaxial Josephson junction. As shown in FIG. 36 (f), when a CeO ₂ film 15 is deposited on a part of the MgO substrate 14 and a copper oxide superconductor 16 is deposited on it, the MgO substrate 14 and the CeO ₂ film 15 are separated from _{each other.} Therefore, the crystal orientation of the copper oxide superconductor 16 is different. As a result, the boundary between them (shown by the broken line in FIG. 36 (f)) becomes a grain boundary junction. When making such a bond, the CeO ₂ film 1
After depositing 5, there was an important issue how to remove some of them and leave others (eg RPJIJsselstei
jn, JWMHilgenkamp, D.Terps-tra, J.Flokstra, and
H. Rogalla, in “Advances in Cryogenic EngineeringM
aterials ”Volume 40, Edited by RPReed, FRFicke
tt, LTSummers, and M.Stieg, (Plenum press, New Yor
k, 1994) pp.353-360).

As one method of removing a part of the CeO ₂ film, there is a method of depositing a CeO ₂ film over the entire surface of the substrate, applying a resist on the CeO ₂ film, exposing / developing, and etching with an Ar ion beam. Can be mentioned. But with this method CeO
₍₂ ) After removing the film, the surface of the MgO substrate becomes rough due to the damage of the ion beam, and the crystal orientation of the copper oxide superconductor on the MgO substrate is not aligned. there were. Therefore, the complicated process shown in FIG. 36 has been taken. That is, first, the resist 1
A pattern is created by applying and exposing / developing No. 7 (see FIG.
6 (a)), and the CaO film 18 is deposited thereon (FIG. 36).
(B)). The CaO film 18 on one side is lifted off (see FIG. 36).
(C)) The CeO ₂ film 15 is deposited including the remaining CaO film 18 (FIG. 36D). Next, using the fact that the CaO film 18 dissolves in water, the CeO ₂ film 15 on one side is lifted off (FIG. 36 (e)), and copper oxide superconductivity such as YBa ₂ Cu ₃ O _7-δ is applied from above. The body 16 is deposited. In the conventional manufacturing method, the grain boundary junction cannot be formed without going through such complicated steps.

On the other hand, in semiconductor devices, as the degree of integration increases, a perovskite type high dielectric constant material is used as a dielectric film in place of a conventional silicon oxide film or a laminated film of a silicon oxide film and a nitride film. It has become possible to be.
However, perovskite-type dielectrics such as Ba _0.5 Sr _0.5 TiO ₃ have the drawback that etching during patterning is difficult (Shibano, Kazuyasu Nishikawa, Applied Physics,
63, pp.1139-1142 (1994)). Chemical etching with halogen plasma is usually used in dry etching of semiconductor devices, but it does not work well for perovskite type dielectrics. This is because the halogen compounds of Ba and Sr have high boiling points and low vapor pressures.
Therefore, there are drawbacks such that it is difficult to obtain etching selectivity with respect to the silicon oxide film, and reaction products having a low vapor pressure remain to cause deterioration of characteristics.

As a magnetoresistive element, for example, a magnetic head for reading a high density magnetic disk utilizing a giant magnetoresistive effect of a magnetic film is known. For example, a magnetoresistive head using a metal multilayer film is well known (C.
Tsang et al., IEEE Trans.Mag., Vol.30, pp.3801-380
6 (1994)), as a magnetic head material having a larger magnetoresistive effect and higher output than such a metal multilayer film, La _1-x AE _x MnO ₃ (AE: Ca, which has a perovskite type crystal structure,
Sr or Ba) has been proposed (Y.Tokura et al., J.Ph.
ys. Soc. Japan, Vol63, pp.3931-3935 (1994)).
However, a thin film of this substance is more difficult to etch than a metal magnetic film, and has a drawback that patterning into a magnetic head shape is difficult.

Further, with the progress of the technique for forming a composite oxide thin film, an oxide, a perovskite-based oxide, an insulator,
Semiconductors, metals, superconductors, ferroelectrics, piezoelectrics, magnetics,
Studies have been conducted on the direction in which various physical properties such as translucency and optical function are integrated and utilized. That is, attempts have been made to obtain a new functional device by epitaxially stacking a plurality of types of substances having different properties. Also in this case, the complex oxide of perovskite group has a drawback that it is difficult to chemically etch and it is difficult to actually form the element shape.

[0010]

As described above, the conventional superconducting element manufacturing process requires many lithography steps and flattening steps, which complicates the manufacturing process and deteriorates the characteristics of the superconductor. However, there is a problem in that such things are likely to occur. Further, when a perovskite type dielectric is used for a semiconductor device, it is difficult to obtain etching selectivity and residues tend to remain. Further, in an element using a perovskite-based oxide such as a magnetoresistive element, there is a problem that it is difficult to manufacture an actual element shape because it is difficult to etch.

The present invention has been made to address such a problem, and a method of manufacturing an oxide thin film element and a superconducting device capable of improving manufacturing efficiency by reducing the number of lithography steps and the like. It is an object of the present invention to provide a method for manufacturing an element, and another object of the method for manufacturing a superconducting element of the present invention is to prevent characteristic deterioration of a superconductor thin film due to a lithography process. Another object of the present invention is to provide a method of manufacturing an oxide thin film element in which the pattern formability of a perovskite-based oxide thin film is improved. Furthermore, it is an object of the present invention to provide a superconducting element in which deterioration of superconducting characteristics due to diffusion of oxygen or the like is prevented, while reducing the number of manufacturing steps.

[0012]

According to the method of manufacturing an oxide thin film element of the present invention, as described in claim 1, an oxide is prepared by supplying an organic metal compound and active oxygen to a substrate in a vacuum chamber. In the method for producing an oxide thin film element having a step of producing a thin film, in the step of producing the oxide thin film, the ratio of the molecule supply density of the organometallic compound and the supply density of the active oxygen on the substrate is spatially changed. It is characterized by changing to.

According to the method for producing an oxide thin film element of the present invention described above, in particular, in the process of producing the oxide thin film, the oxide thin film epitaxially grown with good crystallinity and the crystallinity poor A feature of the present invention is that an oxide thin film which is easily etched and a thin film having two or more kinds of portions selected from a conductive thin film containing 10 at% or more of carbon are produced.

The method for manufacturing a superconducting element of the present invention is
As described in claim 3, a step of producing a Ce oxide thin film by supplying a β-diketone complex of Ce and active oxygen to a substrate in a vacuum chamber, and superconducting on the Ce oxide thin film. In the method for manufacturing a superconducting element having a step of stacking a body thin film, in the step of producing the Ce oxide thin film, the molecular supply density of the β-diketone complex of Ce on the substrate and the supply density of the active oxygen. It is characterized by spatially changing the ratio with.

According to the method for producing a superconducting element of the present invention described above, particularly, in the step of producing the Ce oxide thin film, epitaxial growth is performed with good crystallinity.
CeO ₂ insulating film, poor crystallinity and easy to etch CeO ₂
It is characterized by producing an insulating film and a thin film having two or more kinds of portions selected from a conductive thin film containing Ce and C and O as main components.

Further, the superconducting element of the present invention is a superconducting element comprising a superconducting layer and an insulating layer formed in contact with the superconducting layer, wherein the insulating layer is at least 1 selected from Al, Si and rare earth elements. It is characterized in that 1 at% or more of carbon is contained in the peripheral portion of the insulating layer which is made of an oxide crystal containing a seed element and is in contact with the superconducting layer.

[0017]

In the manufacturing method of the present invention, β-on the substrate
The ratio of the molecular beam supply density of an organometallic compound such as a diketone metal complex to the supply density of active oxygen such as atomic oxygen or ozone is spatially changed. Here, FIG. 1 shows the metalor-ganic molecular-beam epitaxy.
method; hereinafter abbreviated as MONBE method), the state of the thin film obtained when the molecular beam supply amount and the active oxygen supply amount of the β-diketone metal complex used as an example of the organometallic compound are changed. Is. This is the result of observing the growth process of the thin film by reflection high-energy electron diffraction (RHEED) and conducting X-ray diffraction, resistivity measurement, and etching experiment after film formation.

In the present invention, for example, the following thin films can be formed according to the three types of regions (A), (B) and (C) shown in FIG. That is, in the region (A) where the active oxygen flux such as atomic oxygen flux or ozone flux is sufficiently higher than the organometallic molecular flux (10 times or more in FIG. 1), an epitaxially grown oxide thin film with good crystallinity is obtained. This film has the property that it is difficult to etch with hydrochloric acid or the like. In the region (C) where the active oxygen flux is insufficient with respect to the organometallic molecular flux (less than 4 times in FIG. 1), the oxide thin film contains carbon at 10 at% or more. Crystal film with resistivity
It has a conductivity of less than 1 Ωcm and is not easily etched by hydrochloric acid or the like. (B) In the region between the above-mentioned regions (A) and (C) (in FIG. 1, the active oxygen flux is 4 times or more and less than 10 times the organometallic molecule flux), there is no epitaxial growth and oxidation with poor crystallinity It becomes a thin film and has the property of being easily etched by hydrochloric acid or the like. Further, the film obtained in the region (B) is more easily etched by Ar ion milling or the like than the film obtained in the region (A) or the region (C).

As described above, by spatially changing the ratio of the molecule supply density of the organometallic compound to the supply density of the active oxygen on the substrate, for example, a plurality of electric characteristics and crystallinities different in the same thin film layer can be obtained. A thin film having a portion can be manufactured. Therefore, for example, by spatially changing the supply density of active oxygen, by spatially changing the ratio of the molecular metal supply density of the organometallic compound and the active oxygen supply density,
In the same thin film layer, at least two or more portions of the thin film of the (A) region, the thin film of the (B) region, and the thin film of the (C) region can be formed. Therefore, according to the manufacturing method of the present invention, for example, a pattern forming method that does not require a photolithography step can be realized, and an oxide thin film that easily etches an unnecessary portion can be obtained.

The reason why the properties of the thin film change as described above is as follows. The region (A) is a region in which the active oxygen supply density is sufficiently high relative to the organometallic molecule supply density to the substrate. By sufficiently supplying the active oxygen in this manner, the contamination of carbon impurities is prevented by the secondary ion mass spectrometer. It is below the detection limit of (SIMS). Therefore, an oxide thin film having good crystallinity and grown epitaxially on the base is obtained, and this film is not easily etched by acid, ion milling, plasma etching or the like. The region (C) is a region where the active oxygen supply density is low relative to the organometallic molecule supply density to the substrate. In such a case, the ligands of the organometallic molecules cannot be sufficiently removed from the film, For example, carbon is incorporated into the film in the range of 10 to 50 at% and the oxidation of the metal element becomes insufficient. Therefore, a thin film having conductivity having a resistivity of less than 1 Ωcm can be obtained because it contains atoms having an electronic state close to that of a metal.

The region (B) is a region intermediate between the regions (A) and (C). In such a case, carbon of 10 at% or less and 1 at% or more is mixed in the film as an impurity, and A metal ion having a valence lower than that of an ordinary oxide is mixed. As a result, without epitaxial growth,
It becomes an oxide thin film with poor crystallinity, acid, ion milling,
The film is easily etched by plasma etching or the like.
Therefore, in order to effectively use the region (B), it is desirable to use a metal ion that can have a valence state lower than the valence state in a normal oxide. Examples of such ions are Ti ⁴⁺ (Ti ³⁺ ), V ⁴⁺ (V ³⁺ , V ²⁺ ), Cr
³⁺ (Cr ²⁺ ), Mn ³⁺ (Mn ²⁺ ), Fe ³⁺ (Fe ²⁺ ), Co ³⁺ (C
o ²⁺ ), Ni ³⁺ (Ni ²⁺ ), Cu ²⁺ (Cu ¹⁺ ), Nb ⁵⁺ (Nb ³⁺ ), M
o ⁴⁺ (Mo ³⁺ , Mo ²⁺ ), Ru ⁴⁺ (Ru ³⁺ , Ru ²⁺ ), Re ⁶⁺ (R
e ⁴⁺ , Re ²⁺ ), W ⁵⁺ (W ⁴⁺ , W ³⁺ , W ²⁺ ), and other transition metal element ions, Ce ⁴⁺ (Ce ³⁺ ), Pr ⁴⁺ (Pr ³⁺ ). , Sm ³⁺ (S
m ²⁺ ), Eu ³⁺ (Eu ²⁺ ), Tb ⁴⁺ (Tb ³⁺ ), Tm ³⁺ (Tm ²⁺ ), Y
Examples are rare earth element ions such as b ³⁺ (Yb ²⁺ ). In addition, a valence state lower than that in a normal oxide is shown in parentheses. By using such an oxide containing a metal ion, it becomes possible to more stably manufacture the above-mentioned thin films having different properties.

Next, the operation of the method for manufacturing a superconducting element of the present invention will be described more specifically. When a copper oxide superconductor is used as the superconductor, it is desirable to combine CeO ₂ with good lattice matching as the insulating film.

(I) In the same thin film layer by one film formation,
For example, a film containing Ce, C, and O as main components in the region (C), which functions as a resistor, and C for separation in the region (A).
The eO ₂ insulating film can be formed in any planar shape. A flat surface is obtained over the entire area of this film.

(Ii) In the same thin film layer by one film formation,
The crystallinity of the (A) region was good and epitaxial growth was performed.
And CeO ₂ insulating film, (B) CeO poor crystallinity due to area ₂
An insulating film or a film containing Ce and C and O as main components by the (C) region can be formed in an arbitrary plane shape. By laminating an oxide superconductor thin film containing no carbonic acid group thereon, superconductivity can be obtained on the film of the (A) region, and epitaxial growth does not occur on the film of the (B) or (C) region. By mixing carbon, a film that does not exhibit superconductivity can be obtained.

(Iii) In the same thin film layer by one film formation,
The crystallinity of the (A) region was good and epitaxial growth was performed.
And CeO ₂ insulating film, it is possible to fabricate the easy CeO ₂ film soluble in (B) Crystalline poor acid by the area of any planar shape. By etching this with acid etc., without going through the process of resist coating, exposure and development,
The CeO ₂ insulating film can be patterned.

(Iv) In the same thin film layer by one film formation,
A resistive film containing Ce and C and O as main components in the (C) region, and CeO having poor crystallinity in the (B) region and easily dissolved in an acid or the like.
_{The two} films can be made in any planar shape. By etching this with acid etc., Ce, C and O can be obtained without going through resist coating, exposure and development processes.
It is possible to pattern the resistance film mainly composed of and.

Further, in the superconducting element of the present invention, carbon is contained at 1 at% or more in the peripheral portion of the insulating layer in contact with the superconducting layer, so that the superconducting layer is made of an oxide superconductor containing Nb, NbN or a carbonic acid group. In the case of forming, the deterioration of superconducting characteristics due to the diffusion of oxygen into the superconducting layer can be suppressed. However, if the carbon content in the periphery of the insulating layer is too high, the insulating property of the insulating layer may be impaired, so the carbon content here is set to 50 at% or less, and further 10 at% or less. It is preferable. Also, from the viewpoint of the insulating property of the insulating layer,
The carbon content in the central portion of the insulating layer is preferably set to less than 1 at%, but according to the manufacturing method of the present invention,
Based on the action of (iii), the insulating layer having such a carbon concentration gradient can be easily formed.

[0028]

Embodiments of the present invention will be described below.

First, an example in which the above-mentioned actions (i) to (iv) are specifically applied to the manufacture of a superconducting element will be described. Figure 2
FIG. 3 is a diagram showing a superconducting element of one embodiment to which the manufacturing method of the present invention is applied, specifically a Josephson integrated circuit.
In the Josephson integrated circuit shown in FIG.
A superconducting layer 22 serving as a ground plane is formed on the insulating layer 23 for separation, a resistance film 24, and a portion to be a contact hole 25 formed on the same thin film layer 26 by one film formation. Is formed inside.

That is, when the thin film layer 26 is formed, for example, by changing the supply density of active oxygen,
In the portion corresponding to the isolation insulating layer 23, the supply amount of active oxygen is set to be sufficiently larger than the supply amount of molecules of the organometallic compound ((A) region), and an insulating oxide thin film with good crystallinity grown epitaxially is formed. Form. In the portion corresponding to the resistance film 24, the supply amount of active oxygen is set to be smaller than the supply amount of molecules of the organometallic compound (region (C)) to form a thin film containing 10 at% or more of carbon functioning as a resistor. . In addition, in the portion to be the contact hole 25, the supply amount of active oxygen is set to an intermediate level between the above two types of thin film formation, and an oxide thin film having poor crystallinity and easily etched is formed.

As a specific structure of the thin film layer 26, an CeO ₂ insulating film epitaxially grown as the isolation insulating layer 23 is prepared by using an organic substance containing Ce as an organic metal compound as a thin film forming raw material, and A film containing Ce-CO as a main component is formed as the resistance film 24. In addition, a CeO ₂ insulating film having poor crystallinity is formed in the portion to be the contact hole 25. However, the constituent material of the thin film layer 26 is not limited to the CeO-based material, and may be an oxide containing at least one element selected from Al, Si and a rare earth element. By using a substance, an Al ₂ O ₃ thin film is formed as the isolation insulating layer 23, and an Al—CO based thin film is formed as the resistance film 24.
Further, by using an organic substance containing Si as a thin film forming material, a SiO ₂ thin film can be formed as the separation insulating layer 23 and a Si—CO based thin film can be formed as the resistance film 24.

The above-mentioned three kinds of oxide thin films are provided with a mask between a substrate and a gas outlet containing a gas containing active oxygen such as atomic oxygen or ozone, and the outlet has a very strong directivity. By changing the direction of the nozzle while making it a nozzle and scanning the substrate with a beam of a gas containing active oxygen that has been narrowed down, the supply amount of active oxygen is spatially changed according to the formation region of each thin film, By this 1
The same thin film layer 26 can be continuously formed by forming the film once.

The resistance film 24 is patterned into a desired shape when the thin film layer 26 is formed, and is a flat surface continuous with the surrounding isolation insulating layer 23.
Therefore, the lithography process of the resistance film, that is, the resist coating / exposure / development process and the etching process of the resistance film, which are required in the conventional manufacturing method, are unnecessary. Further, the step of flattening the groove around the resistance film by spin-on-glass (SOG) or the like, which is necessary in the conventional example shown in FIG. 34, is also unnecessary. With these, the number of manufacturing steps can be significantly reduced. This is an example of embodying the action of (i) described above.

Further, after forming the thin film layer 26, etching is performed with hydrochloric acid or the like to remove only the oxide thin film portion which is easily etched to form a contact hole 25 to the superconducting layer 22 which becomes a ground plane. To be done. At this time, the isolation insulating layer 23 and the resistance film 24 are not easily etched with hydrochloric acid. Therefore, the contact hole 25 can be formed without performing the resist coating / exposure / development process and the insulating layer etching process. This is an example of embodying the action of (iii) described above.

In the Josephson integrated circuit described above, the superconducting layer 2 is formed after the contact hole 25 is formed.
A Josephson junction 30 is formed by laminating 7 and filling the inside of the contact hole 25 with the superconducting layer 27, and further forming the isolation insulating layer 28 and the superconducting layer 29. In this case, the superconducting layers 22, 2
7 and 29 may be an oxide superconductor film or a metal superconductor film such as Nb or NbN. Considering that the thin film layer 26 is an oxide thin film and can be epitaxially stacked with the insulating layer 23 and the like, it is desirable to use a copper oxide superconductor film for the superconducting layers 22, 27 and 29.

The Josephson integrated circuit (superconducting element) of the above-mentioned embodiment has the following structural advantages in addition to the advantages of the manufacturing process described above. First, the interface between the isolation insulating layer 23 corresponding to the (A) region and the portion to be the contact hole 25 corresponding to the (B) region, and the isolation insulating layer 23 corresponding to the (A) region and (C). At the interface with the resistance film 24 corresponding to the region, there is a transition region where the carbon concentration in the film changes because the active oxygen supply density changes within a finite distance. The width of this transition area is the minimum pattern width
It is about 1/10 to 1/1000. In these transition regions, the film quality gradually changes, and since the constituent elements of each film are similar, thermal stress is less likely to occur at each interface even if a temperature cycle is applied, and cracks and the like are less likely to occur. can get. On the other hand, for example, Nb or N
In a conventional superconducting element using bN, Mo is mainly used as a resistance film, and SiO ₂ is used as an insulating layer.Since the materials of the resistance film and the insulating layer are completely different, the thermal expansion coefficients of the two are significantly different, Defects such as cracks between the resistance film and the insulating layer or easy peeling of the film from the temperature during the device fabrication (for example, 700K) to the temperature during device operation (for example, 4.2K). Had. The superconducting device of the above embodiment overcomes these drawbacks.

Second, the insulating layer 23 around the contact hole 25 has, for example, 1a as a transition region even after etching.
A region containing some carbon of about t% or more remains.
The resistance film 24 also contains carbon. This has the following advantages when Nb is used for the superconducting electrode.
That is, when Nb is in contact with the oxide, there is a problem that oxygen is diffused into Nb and the superconducting property is deteriorated. On the other hand, when Nb is deposited in the contact hole 25, the insulating layer 23 around the contact hole 25 has a layer containing some carbon as a transition region.
In other words, since the peripheral portion of the insulating layer 23 that is in contact with the Nb superconductor contains some carbon, Nb-CO is formed at the interface between the insulator and the superconductor, which suppresses the diffusion of oxygen to the superconducting electrode. In addition, it is possible to prevent the characteristic deterioration of the superconducting conductive electrode in the contact hole 25. Similarly, when Nb superconductor is laminated on the resistance film 24 containing carbon as well, Nb-CO is formed at the interface, so that diffusion of oxygen to the superconducting electrode is suppressed and deterioration of superconducting characteristics is prevented. You can When the oxide and Nb are in contact with each other, if a crystalline NbC _0.25 O _0.75 film having a thickness of about 2.5 to 3 nm is interposed between them, diffusion of oxygen to the superconducting electrode is suppressed, and deterioration of superconducting characteristics is caused. To be suppressed is already SIRa
ider, RWJohnson, TSKuan, REDrake, and RAPo
llak, IEEE Transon Magnetics, MAG-19 , 803 (1983).

Further, when NbN is used for the superconducting electrode, the following advantages occur. Since the periphery of the contact hole 25 and the resistance film 24 contain carbon, a slight amount of carbon diffuses from there to the superconductor, which helps improve the superconducting property of the NbN superconductor or prevent deterioration of the superconducting property. That some of the carbon in the NbN film is improved to the T _c is mixed, for example EJCukaukas, WLCarter, and
SBQadri, J. Appl. Phys. 57 , 2538 (1985). Besides, for example, (Ba _1-x Sr _x ) ₂
Cu _{1 + y} O _{2 + 2y + 5} (CO ₃ ) _1-y and Y _1-x Ca _x Sr ₂ Cu
_Even when a layered copper oxide superconductor containing a carbonate group such as _{2 + y} (CO ₃ ) _1-y O _z is used, the presence of carbon also improves the superconducting properties or prevents the deterioration of the superconducting properties as described above. Be useful. However, in order to sufficiently suppress such oxygen diffusion, the width of the region containing 1 at% or more of carbon is preferably 2 nm or more.

FIG. 3 is a view showing a superconducting device of another embodiment to which the manufacturing method of the present invention is applied, specifically, a passive microwave device using an oxide superconductor containing no carbonate group. The basic structure is the same as in FIG. In this case, it is desirable to use, as the substrate 31, sapphire that has a small dielectric loss and can easily obtain a large-sized substrate.
In the passive microwave device shown in FIG. 3, on the sapphire substrate 31, an epitaxial insulating layer 32 having good crystallinity by the (A) region and a layer 33 by the (C) region are provided.
The thin film layer 34 is formed in the same thin film layer 34 once. The oxide superconductor 35 is deposited on the thin film layer 34, while the oxide superconductor film 36 having superconductivity is formed on the insulating layer 32 formed by the region (A).
A film 37 that does not exhibit superconductivity is formed on the layer 33 of the region (C) because it does not grow epitaxially and carbon is mixed. Therefore, the lithography process after the superconducting film deposition, which is necessary in the conventional manufacturing method, is not necessary. This is an example in which the above-mentioned action (ii) is embodied.

Similarly, in the passive microwave device in which the oxide superconductor is deposited on the sapphire substrate, an embodiment in which the action (iii) is embodied will be described. FIG. 4 is a diagram showing the manufacturing process of the passive microwave element of this embodiment.
First, as shown in FIG. 4A, an epitaxial insulating layer 39 having good crystallinity due to the (A) region and a crystallinity having poor crystallinity due to the (B) region are formed in the same thin film layer 38 by one film formation. And an insulating layer 40 that is easily melted. Then, the insulating layer 40 having poor crystallinity is etched with hydrochloric acid to leave only the portion of the insulating layer 39 epitaxially grown (FIG. 4).
(B)). When a copper oxide superconductor is deposited thereon, an oxide superconductor film 41 exhibiting superconductivity is formed on the epitaxially grown insulating layer 39, and the sapphire substrate 31 is formed.
The portion 42 deposited directly on it does not exhibit superconductivity due to reaction with the substrate. Therefore, the passive microwave element can be manufactured without performing the patterning process after the deposition of the superconductor film. Also, when a Si substrate is used as the substrate, the same effect can be obtained because the reaction between the substrate and the superconductor film occurs.

[0041] On the other hand, it does not react with SrTiO ₃ and LaAlO ₃ as copper oxide superconductor as the substrate, in the case of using a substrate having excellent lattice matching, copper oxide superconductor deposited directly on the substrate also superconducting Shows sex. In this case, the upper and lower superconducting films can be spatially and electrically separated by making the epitaxial insulating layer thicker than the superconducting film. This technology is effective for superconducting wiring of passive microwave devices and superconducting integrated circuits. In the case of a stripline delay line, it is important how long a superconducting wire can be drawn on a substrate with a limited area. As shown in FIG. 5, by connecting the upper superconducting wire 43 and the lower superconducting wire 44 with the connecting superconductor 45 at the center of the substrate, a delay line with high area utilization efficiency can be easily manufactured.

FIG. 6 is a bi-epita to which the action (iii) is applied.
It is a figure which shows the manufacturing process of a xial Josephson junction. That is, first, as shown in FIG.
An insulating layer 48 having good crystallinity and epitaxially grown and an insulating layer 49 having poor crystallinity and easily soluble in acid are formed in the same thin film layer 47 by one film formation. Then, only the insulating layer 49 having poor crystallinity is etched with hydrochloric acid to leave only the epitaxial insulating layer 48 (FIG. 6B). On top of that YBa ₂ Cu ₃
A bi-epitaxial Josephson junction can be formed by depositing a copper oxide superconductor film 50 such as O ₇ . Compared with the conventional example shown in FIG. 36, this eliminates the need for resist coating / exposure / development, CaO deposition, and two lithography steps, resulting in a significant improvement in manufacturing efficiency.

The function (iv) described above can be applied to patterning of the resistance film of the Josephson integrated circuit. It can also be applied to a passive microwave device in which a copper oxide superconductor is deposited on a LaAlO ₃ substrate. When a Ce-CO-based thin film patterned according to the action of (iv) is produced on a LaAlO ₃ substrate and a copper oxide superconductor is deposited on it, La
The portion deposited on AlO ₃ exhibits superconductivity, and the portion deposited on the Ce-CO thin film does not exhibit superconductivity because it does not grow epitaxially and contains carbon. Therefore, the lithography process after the superconducting film deposition, which was necessary in the conventional manufacturing process, becomes unnecessary.

Next, more detailed examples of the present invention will be described.

Example 1 First, the film forming apparatus used in the following examples will be described with reference to FIG. The MBE film forming apparatus shown in FIG. 7 has five Knudsen cells each containing, for example, Pb, Sr, Ca, Dy, and Cu, which are raw materials for lead-based layered copper oxide superconductors, in the film forming chamber 51. 52, 53, 54, 55, 56 and a gas source nozzle 57 are arranged. Further, an ECR gun 58 is installed in the film forming chamber 51, and it is possible to irradiate the substrate 60 set on the substrate holder 59 with active oxygen. The supply amount of the active oxygen-containing gas to the film forming chamber 51 was, for example, 0.7 to 4.0 sccm, and the incident power on the plasma was 100 W. With this MBE film forming apparatus, a (Pb ₂ Cu) Sr ₂ (Dy, Ca) Cu ₂ O _{8 + δ} superconductor film can be epitaxially grown in a layered manner.

The film forming chamber 51 is evacuated by a cryopump (not shown) having an evacuation speed of 2000 l / s, and the film forming chamber 51 is evacuated.
The internal pressure is measured by the ion gauge 61. In the film formation of this embodiment, the pressure in the film formation chamber 51 is 1.2 to 5.6 × 10 ⁻³ Pa.
Met. The film forming chamber 51 is further provided with an electron gun 6 which is differentially evacuated.
2 and a fluorescent screen 63, RHEE in the growth process
D observation is possible. In this example, the electron acceleration voltage was 25 to 30 kV.

As the substrate 60, a single crystal SrTiO ₃ (10
Using the (0) plane and (110) plane, a heater (not shown)
Heated to 50-850 ° C. Although not shown, the substrate 6
A crystal oscillator type film pressure gauge is set immediately below 0, and is configured so that the molecular beam intensity from the Knudsen cells 52, 53, 54, 55, 56 and the gas source nozzle 57 can be monitored.

The gas source nozzle 57 is connected to an organic metal gas source source 64, which is provided outside the film formation chamber 51 and serves as a source for producing an oxide thin film. Organic metal gas source source 64
Is, for example, a φ70 ICF provided on the side wall of the film forming chamber 51.
It is connected to a gas source nozzle 57 from a flange (not shown) via a gas supply pipe 65 of 1/4 inch.
That is, the organometallic gas source source 64 can be easily installed by providing one φ70 ICF flange in the film forming chamber 51.

As the organometallic compound raw material, a β-diketone complex of Ce was used. Specific compounds include tetrak
is [2,2,6,6-tetramethyl-3,5-heptanedionato] cerium
(Abbreviation: Ce (thd) ₄ ), tris [2,2,6,6-tetramethyl-3,5-
heptanedionato] cerium (abbreviation: Ce (thd) ₃ ), tetrakis
[6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedionato] c
erium (abbreviation: Ce (fdh) ₄ ), 1,10-phenanthrolinetris
[2,2,6,6-tetramethyl-3,5-heptanedionato] cerium (abbreviation: Ce (thd) ₃ phen), 1,10-phenanthrolinetris [6,6,6
-trifluoro-2,2-dimethy1-3,5-hexanedionato] cerium
(Abbreviation: Ce (fdh) ₃ phen) or the like can be used. These β-diketone complexes of Ce have a sufficient vapor pressure between 100 and 300 ° C, and decompose at temperatures above 300 ° C in the presence of oxygen gas to deposit Ce. Is suitable.

The mass analysis results of the vapor components when Ce (thd) ₄ and Ce (thd) ₃ phen were heated in vacuum showed that [Ce (th
d) ₃ ] ⁺ (M = 689) is the most common. Therefore, from the beginning to raw materials
If Ce (thd) ₃ is used, unnecessary ligand components can be reduced. In the production method of the present invention, other rare earth elements such as Pr, Dy, and Eu, and β-diketone complexes such as Al and Si can be used as the raw material instead of the organometallic compound of Ce. However, considering the compatibility such as lattice matching between the epitaxially grown oxide film and the copper oxide superconductor, it is desirable to use Ce β 2 -diketone complex to form an insulating film containing CeO ₂ as a main component.

Next, a specific example of thin film production will be described. The organometallic compound raw material used in the following thin film preparation examples is C
e (thd) ₃ , also known as tris (dipivaloymethanate) cerium, is abbreviated below as Ce (dpm) ₃ . Its structural formula is shown in FIG.
Shown in The chemical formula is (C ₁₁ H ₁₉ O ₂ ) ₃ Ce, and the molecular weight is
689.9. According to the TG-DTA curve, the melting point is 2
The temperature is 00 ° C, and the weight loss due to sublimation begins at about 160 ° C, and there is an exothermic peak near 320 ° C, which is thought to be due to the decomposition of the raw material. Therefore, the raw material temperature is preferably 150 ° C or higher and 200 ° C or lower to prevent deterioration. Moreover, in order to prevent decomposition in the pipe of the gas transportation route, it is desirable that the pipe temperature is 320 ° C or lower.

FIG. 9 shows a detailed view of the vicinity of the organometallic gas source 64 and the gas source nozzle 57. Raw material container 6
The organometallic compound raw material stored in 41 is stored in an oven 643 having a heater 642 provided outside the film formation chamber 51.
The gas that has been heated to a constant temperature of 190 ° C and sublimated is guided to the vicinity of the substrate 60 by the gas supply pipe 65 heated by the three heaters 651a, 651b, and 651c, and is irradiated from the gas source nozzle 57 toward the substrate 60. It In order to control the pressure of the transportation route and the gas supply amount, 2
Two variable leak valves VLV1 and VLV2 are provided. At the time of gas supply, the valve V1 and the variable leak valve VLV1 were fully opened, the other valves V2, V3, and VLV2 were closed, and the gas supply amount was controlled by controlling the temperature of the oven 643.

The raw material gas pressure was measured by an absolute pressure gauge 644 (in this embodiment, MKS Co., Ltd. Baratron Type315 (10 Torr Head) (20
It can be used up to 0 ° C) and Type 270-4 (Elctronics Unit) in combination). Variable leak valve VL
The raw material container 641 has the lowest temperature in the oven 643 and the variable leak valves VLV1, VLV2 and Baratron absolute pressure gauge 644 are set about 10 ° C higher than that in order to prevent the raw material from aggregating to V1, VLV2 and Baratron absolute pressure gauge 644. Has been done. The 1 / 4-inch gas supply pipe 65 arranged outside the oven 643 has heaters 651 a and 651.
It is divided into three regions and heated by b and 651c. The tip of the gas supply pipe 65 is a nozzle 57 having a hole with a radius of 0.11 mm.
A shutter 66 for blocking the molecular beam flux to the substrate 60 is provided at the tip of 7.

Here, in order to stably supply the gas,
It is important to heat the gas supply pipe 65 uniformly. For example, if a bellows valve, a VCR joint, or the like is arranged in the pipe 65 between the oven 643 and the film forming chamber 51, the temperature is locally lowered, the raw material is deposited as powder, and the pipe is clogged. Therefore, only a trace amount of Ce oxide can be deposited on the substrate 60. Therefore, the gas supply pipe 65 between the oven 643 and the film forming chamber 51 is not provided with a bellows valve, a VCR joint or the like which causes a temperature decrease. In addition, a tape heater is used as the heater 651a because it is easy to maintain uniform heating.

If the temperature control in the vicinity of the gas source nozzle 57 is insufficient, when the substrate 60 is heated to 700 to 800 ° C., the radiation raises the temperature by about 50 mm from the tip of the nozzle 57, or the temperature rises too much. Since the pressure drops too much, adsorption and desorption of the raw material on the inner wall of the pipe occur and the raw material gas pressure fluctuates. Therefore, a heater 651c, a thermocouple TC4, and a temperature controller (not shown) are provided so that the temperature can be controlled independently in the vicinity of the gas source nozzle 57.
Further, the gas source shutter 66 has a shape that also serves as a heat shield plate between the substrate 60 and the vicinity of the nozzle 57 even in the open state. Therefore, the shaft rotation of the shutter 66 needs to be controlled with an accuracy of 14 ° ± 0.5 °.
A stepping motor and a controller were used to open and close the shutter 66 instead of the conventional pneumatic actuator.

By controlling the tip temperature of the gas source nozzle 57 and installing the shutter 66 as described above, the gas source is heated regardless of whether the substrate 60 is heated (up to 800 ° C.) or the shutter 66 for the gas source is opened or closed. The temperature of the nozzle 57 could be suppressed within a range of ± 10 ° C to -2 ° C with respect to the set temperature (250 ° C). When the heater 651c was not provided, the temperature fluctuated at 40 to 240 ° C. First, set the temperature of the nozzle 57 to 2
As a result of changing the temperature to 00 ° C, 250 ° C, and 300 ° C, the deposition rate was high at 250 ° C, although it was small. Was set and the film was formed.

The prepared thin film sample was X-ray using Cu-Kα ray.
Line diffraction was performed, and the amount of deposited Ce was measured by ICP emission spectroscopy. The dissolution test of the sample was conducted in hydrochloric acid for 30 minutes.
However, CeO ₂ film with good crystallinity is not melted by this method,
The amount of deposit cannot be measured. In that case, Sr-C, which easily dissolves in hydrochloric acid, is supplied by supplying Sr from the Knudsen cell under the same film forming conditions.
An eO-based amorphous film was prepared and analyzed by the above method. If the film formation conditions are the same, the CeO ₂ film and the Sr-Ce-O system amorphous film form C
e There is no big difference in the amount of deposition. In addition, some samples are SE
The surface morphology was examined by M and FE-SEM. As a result, a practically sufficient deposition rate of CeO ₂ film in a film forming method (1
2 atomic layers per minute) were obtained. Moreover, the film thickness distribution was made uniform by analyzing the gas release distribution. And the CeO ₂ film
Epitaxial growth was possible on the SrTiO ₃ substrate. Furthermore, by controlling the ratio of atomic oxygen flux or ozone flux to the organometallic molecule flux, three types of thin films, the thin film according to the (A) region, the thin film according to the (B) region, and the thin film according to the (C) region, are controlled. Could be made differently.

The CeO ₂ film is a barrier layer of a Josephson junction using a Y-Ba-Cu-O-based oxide superconductor, a buffer layer between the substrate and the copper oxide superconductor film, and Nd _2-x Ce. _x Cu O ₄ superconductor constituent element, SOI (silicon-on-insulator) substrate,
It has been researched for various uses such as capacitors for silicon devices, and it has been reported that sputtering method, electron beam evaporation method, laser ablation method, and MOCVD method have been used for film formation. There is no.

Generally, when an oxide film of a metal element having a low vapor pressure is grown by the MBE method, it is difficult to evaporate from the Knudsen cell. Also, electron beam evaporation is difficult to control at a slow evaporation rate. Even if the molecular beam intensity is fed back, there is a problem that the evaporation rate oscillates in a cycle of the order of seconds. Therefore, the MOMBE method, in which a low vapor pressure metal can be easily introduced in addition to the existing MBE chamber and the molecular beam flux is stable, is not limited to CeO ₂ and is very useful when a multi-component oxide is grown for each atomic layer. It is valid. However,
Until now, MOM has placed the metalorganic raw material in a room separate from the deposition room.
There have been few reports of oxide film growth by the BE method.

Japanese Patent Laid-Open Nos. 3-60408, 4-16595, K. Endo, S. Saya, S. Misawa, and S. Yoshida, Thin
Solid Films, 206, 143 (1991), K. Endo, S. Misawa,
S. Yoshida, and K. Kajimura, in Advances in Supercon
ductivity V, edited by Y.Bando and H.Yamauchi, (Spri
nger, Tokyo, 1993), p.973, LLHKing, KYHsieh, DJ
Lichtenwalner, and AIKingon, Appl. Phys. Lett. 5
In the five references of 9, 3045 (1991), YBa ₂ Cu ₃ O was prepared by evaporating an organometallic raw material as it was from a Knudsen cell.
An example of producing a _7-δ superconductor film is described. However, these methods cannot utilize the advantage of the gas source MBE method that the raw materials can be exchanged without breaking the vacuum of the film forming chamber, and the film forming chamber cannot be baked. In addition, Japanese Patent Laid-Open No.
-50104, SJ Duray, DBBuchholz, SNSong,
DSRicheson, JBKetterson, TJMarks, and RPH
Chang, Appl. Phys. Lett. 59 , 1503 (1991), K. Kanehori,
S.Saito, N.Sugii, and K.Imagawa, J.Vac.Sci.Techn
ol.A 12 , 130 (1994), the organic metal raw material is heated outside the deposition chamber, and its vapor (including Duray et al. carrier gas) has an oxygen partial pressure of 1.3 × 10 ^-2 〜. 1.3Pa and normal M
It has been reported that a YBa ₂ Cu ₃ O _7-δ superconducting film was produced by guiding the film to a film forming chamber at a pressure considerably lower than that of the OCVD method.

In the film forming method according to this embodiment, the oxygen pressure in the film forming chamber is 1.2 to 5.6 × 10 ⁻³ Pa, which is lower than the above. The mean free path of the organometallic molecule in the present invention is longer than the substrate-nozzle interval, which is a condition that can be called a molecular beam epitaxy method. The mean free path of oxygen gas molecules, ozone molecules, and atomic oxygen is also sufficiently longer than the oxygen source nozzle-substrate distance. Therefore, a means for changing the spatial active oxygen supply density, such as providing a mask between the oxygen source nozzle and the substrate or scanning the substrate with a narrowly focused beam of the active oxygen-containing gas, works sufficiently effectively to provide a sharp slope. Patterns with various boundaries can be formed. Furthermore, since the oxygen pressure in the film forming chamber is low, it is possible to use an organometallic gas source introduced from the outside of the film forming chamber at the same time as MBE growth using a Knudsen cell. Therefore, it can be said that the film forming method according to the present invention is a MONBE method suitable for forming the first multi-component oxide film.

The details of the thin film deposition experiment will be described below. First, an experimental example in which the film thickness distribution is made uniform will be described. The sample for measuring the film thickness distribution is a SrTiO ₃ (100) substrate overlaid with a metal mask and grown for a long time (4 to 6 hours) under the condition that a CeO ₂ film with good crystallinity can be obtained.
The growth conditions were a raw material temperature of 178 ° C., a substrate temperature of 730 ° C., and an oxygen flow rate of 2.58 sccm. First, we conducted experiments on three types of nozzle positions. FIG. 10 shows relative positions (position a, position b, position c) between the substrate 60 and the gas source nozzle 57. The thickness distribution of the prepared sample is measured by a stylus type film thickness meter (alpha-st manufactured by TENCOR).
ep 100 profiler) and converted into a deposition rate (nm / hr), which is shown in FIG. The horizontal axis x is the position on the surface of the substrate 60 in the extension line direction of the nozzle 57, and the center of the substrate 60 is the origin. Since the film forming method of this embodiment is a molecular beam epitaxy method, a sufficiently steep step is formed only by using a metal mask, and the film thickness can be accurately measured.

In the first measurement, since the importance of whether or not the film is deposited is more important than the film thickness distribution, the nozzle 57 was directed toward the center of the substrate as shown in FIG. In this case, the thickness closer to the nozzle 57 is thicker, and the film thickness decreases as the distance from the nozzle 57 increases, and the film thickness has a steep distribution (indicated by ◯ in FIG. 11). On the other hand, assuming that gas molecules are uniformly discharged from the holes of the nozzle 57 in all directions and follow the cosine law, the angle and position of the nozzle 57 are set so that the film thickness in the substrate 60 is as uniform as possible. The position b is set. At the nozzle position b, the film thickness distribution could be suppressed to ± 15%, but it still has a rising distribution (indicated by ▲ in FIG. 11). This indicates that the gas emission distribution has directivity. That is, it is considered that the nozzle 57 has a directivity because the hole of the nozzle 57 has a cylindrical shape with a finite thickness.

To consider this problem, first, the nozzle 57
Estimate the mean free path of the organometallic gas inside. When the raw material temperature is 178 ° C., the gas pressure p _B measured by the Baratron absolute pressure gauge is 8.9 Pa. 1/4 inch pipe (length
The pressure p _N inside the nozzle is estimated to be 7.6 Pa, considering the pressure drop at 0.6 m (however, viscous flow region) and the temperature difference between the Baratron absolute pressure gauge and the nozzle (difference between 188 ° C and 250 ° C). On the other hand, the diameter d of the Ce (dpm) ₃ molecule is
It is estimated to be 3/4 to 1 nm of the volume occupied by (dpm) ₄ . Therefore, the average degree of freedom stroke λ = k _B T / (2 ^1/2 πd ² p _N )
= 0.214 mm, the nozzle hole radius and length (described later)
Is about the same. Therefore, it is considered that the inside of the pipe before the nozzle hole is a viscous flow region, but the gas flow from the nozzle hole to the substrate may be treated by simple gas molecule kinetics in the molecular flow region. Below, the gas discharge distribution from the nozzle will be considered by a simple gas molecule kinetic theory assuming a molecular flow.

In general, the number of gas molecules dq released per unit time within the range of the solid angle dω from the nozzle hole area S _{N in} the direction of the emission angle θ is

[Equation 1] BB Dayton, in 1956 Natl.Symp.Va
c.Technol. Trans. (Pergamon, 1957) p.5. Here, n is the molecular density [m ^-3 ] and ν is the average velocity (in this case 126 [m / s]). Assuming L = 0, T is always 1
Is the case of the cosine law. In the case of a hole on a cylinder of radius R with a finite length L, T represented by
The factor of (L / R, θ) is applied.

[0066]

[Equation 2]

(Equation 3)

[Equation 4] Below, consideration will be given to the actual positional relationship between the substrate and the nozzle (FIG. 10). The distance between the center of the substrate and the center of the nozzle hole is Z in the height direction.
_0, and X ₀ in the horizontal direction, the angle between an extended line of a normal line and the nozzle pipe of the substrate and the nozzle angle phi _0. The distance between a certain position on the substrate and the nozzle hole is r, and the angle formed by the line with the nozzle pipe extension line is the emission angle θ. The angle between the molecular beam and the substrate normal at a certain position x on the substrate is φ ₀ −θ = tan
⁻¹ [(X ₀ + x) / Z ₀ ]. Supposing the area on the substrate surface within a solid angle dω as S, dS is a function of the position x on the substrate surface and dω = cos (φ ₀ −θ) / r ² dS
= Cos (φ ₀ −θ) ³ / Z ₀ ² dS. Therefore, the number of molecules that reach a certain position on the substrate per unit area per unit time is represented by the following formula.

[0067]

(Equation 5) Using this, it was found that the experimental results of FIGS. 11A and 11B can be explained by assuming that the wall thickness L of the nozzle hole is the same as the radius R (= 0.11 mm). This is a value that is easy to manufacture a nozzle.
Therefore, assuming that the case of L = R in the equation (5) is followed, the nozzle angle and position are set so that the film thickness is as uniform as possible within the substrate. For nozzle position c, φ ₀ = 63
°, X ₀ = 22 mm, Z ₀ = 38 mm. The measurement result of the film thickness distribution is indicated by a black circle in FIG. The distribution was suppressed to within ± 5% on the substrate 60 having a diameter of 20 mm, including variations in measurement. The three curves in FIG. 11 are the results of fitting the equation (5) to the experimental points by inserting a common value for nνS _N ,
The experimental results are almost reproduced. The slightly lower deposition rate in the measurement result of c is considered to be due to the change with time of the raw material.

From the above experiments, it was found that the optimum position can be set in the setting of the nozzle position and angle in the MOMBE method by using the equations (1) to (5) of the gas molecule kinetic theory assuming the molecular flow. It was However, looking at FIG. 11 in detail, there is a slight discrepancy between the theoretical curve and the actual experimental data, which indicates that the directivity is slightly stronger than the equation of gas molecule kinetic theory assuming molecular flow. Therefore, after designing to the optimum value using equations (1) to (5), the position and angle of the nozzle 57 are finely adjusted (4 to 5 degrees in angle) in consideration of the fact that the directivity is slightly stronger than that. It is desirable to

The position of the gas source nozzle 57 was determined on the basis of the above-described uniform film thickness distribution experiment. In the following, the dependence on the film forming parameters such as the raw material temperature, the substrate temperature, the substrate orientation, and the oxygen pressure will be described. The position of the gas source nozzle 57 is c in FIG. 10, the temperature from the gas supply pipe 65 to the gas source nozzle 57 is set to 250 ° C., and Sr
This is the result of growing the TiO ₃ substrate 60 for about 30 minutes.

First, the dependence on the temperature of the raw material oven will be described. The required deposition rate is 2 atomic layers / 1 min = 3.78 × 10 used for the growth of the c-axis oriented film of layered copper oxide.
^-7 [mol m ^-2 s ^-1 ]. The gas supply rate from the gas source nozzle 57 was evaluated by a crystal oscillator film thickness meter. Here, the weight of organic substances adsorbed on a water-cooled substrate (in this case, a crystal with gold electrodes attached)
It was measured by a change of 1 minute α = Δf / Δt [Hz / min]. In addition, a CeO ₂ film was deposited on a SrTiO ₃ substrate heated to 700 ° C., and the deposited amount was examined by ICP emission spectroscopy. The oxygen flow rate during film formation is 4.0 sccm. FIG. 12 shows the dependence of the deposition rate and the amount of Ce deposition on the temperature of the raw material oven.

At a raw material temperature of 188 ° C. or higher, the required deposition rate (1
(CeO ₂ bilayer) per minute. Gas supply rate is also C
The eO ₂ deposition rate also shows a thermal activation type with an activation energy of 18300K. Therefore, it is understood that the film is not deposited by the desorbed gas from the wall of the pipe or the nozzle, but the sublimation process of the raw material in the oven controls the film deposition as expected. The slight variation in the data in FIG. 12 is considered to be due to the change over time in which the amount of sublimation gradually decreases in the organometallic raw material. Even at the same source temperature (188 ℃), after 10 days of experiment, the source gas pressure and deposition rate decreased by nearly 10%. Even in the one-day experiment, the raw material gas gradually decreases after the raw material temperature is raised to a predetermined temperature. 1.5 hours after the raw material temperature was around the desired temperature, the raw material gas pressure decreased by about 1.5% during the 30-minute film growth, but after 6 hours, the gas pressure change during the 30-minute film growth. Was less than 0.3%. In the gas source of this example, the molecular beam flux on the order of seconds to minutes is stable, but when growing for a long time of 2 hours or more, it is necessary to wait 6 hours or more after raising the raw material temperature. .

Next, the raw material gas supply rate is estimated. Generally, the frequency change Δf [Hz] of the crystal oscillator is proportional to the weight Δm [kg m ⁻² ] of the film attached per unit area. Considering the natural frequency of the crystal unit used and the relative position with respect to the substrate, the incident molecular beam intensity Γ [mol m ^-2 s ^-1 ] on the substrate is [Hz / min] is calculated by the following formula.

Γ = 0.4 / (8.135 × 10 ⁶ × 689.9 × 10 ⁻³ × 60) α = 1.19 × 10 ⁻⁹ α (6) On the other hand, by adsorbing an organic metal on the substrate, ICP emission spectroscopy
The organometallic gas supply rate was also obtained by the method of analyzing Ce. It was adsorbed on a SrTiO ₃ substrate cooled to −10 ° C. in vacuum, dissolved in nitric acid, and analyzed. The incident molecular beam intensity Γ was 3.52 × 10 ^-7 [mol m ^-2 s ^-1 ] when the raw material temperature was 188 ° C. This data is plotted by □ in FIG. At this time, the relationship between Γ and α was Γ = 1.13 × 10 ^-9 α (7), which was almost in agreement with Eq. (6). Using equation (7), FIG.
As a result of converting α of the above, it was found that 90% or more of the gas supply amount to the substrate was deposited as CeO ₂ on the substrate heated to 700 ° C.

When the organometallic gas supply rate is evaluated by using the simple gas molecule kinetic theory in the molecular flow region, it is as follows. When the raw material temperature is 188 ° C, the gas pressure p _B measured by the Baratron absolute pressure gauge is 14.1 Pa. Considering the pressure drop in the piping and the temperature difference between the Baratron absolute pressure gauge and the nozzle,
Inside the nozzle, p _N = 13 Pa, molecular density n = p _N / k _B T =
It is 1.81 x 10 ²¹ . On the other hand, the conductance of the nozzle hole
3.24 × 10 ^-6 [m ³ s ^-1 ] when measured using Ar gas
Met. From this value, it is considered that the radius R of the nozzle hole = the wall thickness L of the nozzle hole L = 0.114 mm. Substituting this into Eq. (5), the gas supply rate was estimated to be 3.71 × 10 ^-7 [mol m ^-2 s ^-1 ]. This is in good agreement with the above-mentioned measured value of gas supply rate. That is, it was found that the molecular beam intensity of the MOMBE method can be almost designed by using gas molecule kinetic theory on the assumption that there is a molecular flow after the nozzle hole.

Next, the dependency of the deposition rate on the substrate temperature was investigated. FIG. 13 shows the result of an experiment conducted with the raw material temperature fixed at 188 ° C. and the oxygen flow rate fixed at 4.0 sccm. In the figure, the mark □ at the left end is, as described above, the case where organometallic molecules are adsorbed on the cooled substrate, which is considered to represent the gas supply rate. The deposition rate increases as the substrate temperature rises from 350 ° C, and at a substrate temperature of 700 ° C or higher, 90% or more of the supplied amount is deposited as CeO ₂ . FIG. 13 shows the result of an experiment conducted by irradiating active oxygen with ECR plasma. O ₂ without ECR discharge
As a result of conducting an experiment at a substrate temperature of 700 ° C by flowing a gas, a deposition rate of at least 3/4 or more was obtained compared with the case with plasma. The strong dependence of the deposition rate on the substrate temperature suggests that the thermal decomposition by heating the substrate is more dominant in the Ce deposition than the decomposition by active oxygen at present.

In MOCVD growth of CeO ₂ using Ce (dpm) ₄ , it has been reported that the deposition rate rapidly decreases at a substrate temperature of 500 ° C. or higher. This is because thermal decomposition occurs not in the substrate but in the gas phase in the reaction tube containing oxygen at a pressure of 2000 to 3000 Pa. In the MONBE method according to the present invention,
Even if oxygen gas is introduced, the mean free path of organometallic molecules around the substrate is longer than the substrate-nozzle distance, and there is almost no collision between gas molecules after the nozzle. Therefore, the phenomenon of the decrease in deposition rate during high temperature growth and the decomposition reaction in the gas phase are not observed.

X when deposited on SrTiO ₃ (100) substrate
The substrate temperature dependence of the line diffraction pattern was investigated. Substrate temperature 5
A CeO ₂ film with (100) orientation was obtained at 50 ° C or higher. 14
The height of the main peak, CeO ₂ (200), is shown as a function of growth temperature. A CeO ₂ film with good crystallinity was obtained at a substrate temperature of 650 ° C or higher.

Further, X-ray diffraction and RHE of the obtained thin film
The results of ED observation will be described. 15 to 17 show X-ray diffraction patterns, and FIG. 18 shows RHEED diffraction patterns. The CeO ₂ film on the SrTiO ₃ (100) plane substrate has a (100) orientation according to X-ray diffraction (FIG. 15), and another (111) orientation,
(311) orientation and (331) orientation are not recognized. CeO in Figure 15
_{2 The} (200) peak has an inversion width of 0.23 °, which means that the SrTiO ₃ substrate
It can be seen that the crystallinity is good because the inverse value width of the (100) peak is close to 0.10 °. Also, when seen by RHEED, streaks are only in the initial stage of growth. As the growth progresses, nodules appear in the streak due to the accumulation of 4 to 7 layers, and eventually the spot pattern changes into a diagonal array. For deposits of 10 layers or more,
As shown in (b), the spot pattern becomes perfect, which shows island-like growth. That is, Stranski-Krastanov
It was a mold growth form. The horizontal spacing between spots is
It is almost the same as the substrate streak spacing (corresponding to a lattice spacing of 0.39 nm). Therefore, CeO ₂ (100) // SrTiO ₃ (100), CeO 2
₂ [011 (bar)] // With SrTiO ₃ [001] orientation relation,
CeO ₂ is grown epitaxially on the substrate.
An oblique streak may appear so as to connect the spots, and it is considered that the {111} plane is a facet.

The CeO ₂ film on the SrTiO ₃ (110) plane substrate was found to have (111) orientation from the X-ray diffraction pattern of FIG. As a result of RHEED observation, as shown in FIGS. 18 (a) and 18 (e), it was confirmed that a streak pattern was formed until the end of growth (30 layers), and the (111) -oriented CeO ₂ film was epitaxially grown in a layered manner. Was done. During the growth process, the streak corresponding to the (110) plane spacing (0.276 nm) of the substrate became thinner with the start of growth, the streak almost disappeared in 1 to 2 layer deposition, and then from 3 to 4 layer deposition. A new cycle of streaks appears and grows stronger with growth. The new period corresponds to a lattice spacing of 0.334 ± 0.004 nm. Therefore, the orientation relationship is CeO ₂ (111) // SrTiO ₃ (110)
, CeO ₂ [11 (bar) 0] // SrTiO ₃ [001], CeO ₂ [1
(Bar) 1 (bar) 2] // SrTiO ₃ [1 (bar) 10].
The layered growth of the CeO ₂ (111) oriented film on the SrTiO ₃ (110) surface has been found for the first time in the present invention, without any reports in the past.

If the growth conditions are slightly shifted, SrTiO ₃
Another orientation is also observed on the (110) plane substrate. For example, the substrate temperature is low, the oxygen flow rate is high, and the substrate surface has many steps. In these cases, as shown in the X-ray diffraction pattern in FIG. 17, (110) -oriented CeO ₂
A film is obtained. FIG. 18 shows the RHEED figure in this case.
(F). Although it is a striker, the diffraction intensity is modulated in the vertical direction, and it can be seen that the growth surface has some irregularities. In this case as well, the {111} plane is considered to be faceted. From the RHEED pattern, the orientation relationship is CeO ₂ (110) // SrTiO ₃ (110), CeO ₂ [11 (bar)
0] // SrTiO ₃ [001], CeO ₂ [001] // SrTiO ₃ [1 (bar) 1
It was found to be 0].

In manufacturing a superconducting device, the surface flatness of the CeO ₂ insulating layer or the CeO ₂ buffer layer may be the most important factor. In that case, it is preferable to use a (111) -oriented CeO ₂ epitaxial growth film because layered growth is easy. This is because cations or anions are densely arranged in the (111) plane and the surface energy is low. To obtain a (111) -oriented CeO ₂ epitaxial growth film, for example, S
A substrate surface such as rTiO ₃ (110) surface may be selected.

In order to obtain a flat surface with a (100) -oriented CeO ₂ film, it is effective to add an oxide RE ₂ O ₃ of a trivalent rare earth element RE. As the RE element, for example,
Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, Lu, etc. can be used. The crystal structure of RE ₂ O ₃ is a C-type rare earth structure, and has a crystal structure in which oxygen is regularly depleted from the fluorite type crystal structure. Therefore, (111)
The surface is not a surface with a very low surface energy. For this reason, by adding RE ₂ O ₃ to CeO ₂ ,
Growth with facets on the (111) plane is less likely to occur. As a result, Ce _1-x RE _x O _{2-2x + 1.5x} is less likely to grow in an island shape than CeO ₂ . Considering this principle, the valence of RE is
Even if it is not trivalent, the above effect will occur if it is less than tetravalent.

The results of the actual film forming experiment will be described. While supplying Ce from the organometallic gas source, Dy was evaporated from the Knudsen cell at the same time, and Ce _0.7 Dy _0.3 O _1.85 was formed on the SrTiO ₃ (100) surface substrate. Was prepared, it was confirmed by X-ray diffraction that it had a (100) orientation. As a result of RHEED observation of the growth process, a streak pattern remained even after 12 layers were deposited. In the case of CeO ₂ described above, it can be said that the layered growth is easier than in the case where a complete spot pattern is formed with 10 or more layers. In order to facilitate layered growth, x is preferably 0.1 or more. However, if x is made too large, the advantages of CeO ₂ such as good lattice matching with a copper oxide superconductor and a good insulator will be lost, so x is preferably 0.7 or less.

In the course of the film formation experiment as described above, it was found that epitaxial growth may not occur if the deposition rate is high or the oxygen flow rate is low. RH at that time
In the EED pattern, as shown in FIG. 18C, a ring pattern indicating that the in-plane orientation is random is superimposed on the streak. In an extreme case, it is not CeO ₂ but an amorphous and conductive blackish film. The RHEED pattern in that case is shown in FIG. 18D, which is a figure of only the ring.

Therefore, film growth was performed using both the organometallic gas supply rate and the oxygen flow rate as parameters, and the conditions for epitaxial growth were searched for by RHEED observation and X-ray diffraction. The temperature of the organometallic raw material was changed from 178 ℃ to 190 ℃. The oxygen flow rate was changed in the range of 0.6 to 3.2 times the condition (1.25 sccm) where the copper oxide superconductor was conventionally grown. The substrate temperature was fixed at 700 ° C and growth was performed for 30 minutes. FIG. 19 summarizes the film formation results. ○ indicates RHEED
In the case of epitaxial growth until the end of the growth, the growth conditions (conditions of oxygen flow rate and organometallic gas supply rate) were obtained by X-ray diffraction to obtain a film with good crystallinity. As shown in FIG. 18C, the mark X indicates a growth condition in which a ring overlaps the RHEED pattern indicating epitaxial growth during the growth. The boundary between the two is represented by a dashed line.

20 and 21 show the results of X-ray diffraction when the oxygen flow rate was changed, for comparison. Figure 20 shows Ce (dpm) ₃
CeO when the amount of flux is 3.5 × 10 ^-7 [mol m ^-2 s ^-1 ]
₂ (200) peak oxygen flow rate dependence, and Fig. 21 shows Ce (d
pm) _{3 The} flux amount is 1.9 × 10 ^-7 [mol m ^-2 s ^-1 ]. On the low oxygen flow rate side from the alternate long and short dash line in FIG.
Not only was the ring superimposed on the EED pattern, but at the same time, the CeO ₂ peak of the X-ray diffraction pattern suddenly weakened. That is, it is not epitaxially grown. As shown in FIG. 18D, the Δ mark in FIG. 19 shows the case where the RHEED pattern showing the epitaxial growth is completely invisible and the ring pattern is completely formed. As a result of X-ray diffraction, almost no peak was observed in this sample. Therefore,
It can be seen that it is a polycrystalline body in which amorphous or microcrystalline is aggregated.

When an etching test was conducted on the samples deposited under various conditions with an acid, it was found that the etching rate greatly changed depending on the film quality. As an example, an etching test was performed by placing the hydrochloric acid diluted with concentrated hydrochloric acid about 5 times for 30 minutes. The sample (A) marked with a circle in FIG. 19 has good crystallinity.
Although it is a CeO ₂ epitaxial film, it was not soluble in hydrochloric acid. The sample (B) indicated by x in FIG. 19 is a CeO ₂ film with poor crystallinity that did not grow epitaxially, but was dissolved in hydrochloric acid. As will be described later, the sample (C) marked with Δ in FIG. 19 is a film containing Ce, C, and O as main components and a conductive film, but it was not soluble in hydrochloric acid. The resistivity of this film was 0.2 Ωcm at room temperature. If the ratio of the active oxygen supply density to the organometallic molecule supply density is further reduced than this, a film having a lower resistivity can be obtained.

From the above experimental results, the growth conditions necessary for the epitaxial growth of CeO ₂ could be understood. With the required deposition rate described above, epitaxial growth could be performed with an oxygen flow rate of 4.00 sccm. This flow rate is
Rather than growing copper oxide superconductors using cells 3
Although it is twice as high, it is still within the range where layered copper oxide can be grown. By the way, a pure ozone source may be used as the active oxygen source instead of the ECR plasma active oxygen source.
Here, the pure ozone source is an ozone-containing oxygen gas produced by discharge by an ozonizer that is introduced into an ozone chamber maintained at a low temperature of 77 to 100 K, where only the ozone is liquefied and stored, and 70% or more of which evaporates from it. This is a method of introducing a gas containing ozone to the substrate. As a result of an experiment, in this case, the active oxygen concentration in the gas was higher than that of the ECR plasma oxygen source, and therefore epitaxial growth could be performed up to the condition where the oxygen pressure in the film forming chamber was lower. However, when comparing the active oxygen supply density (in this case, the supply density of ozone molecules), the same experimental result as that of the ERC plasma active oxygen source was obtained.

The film was analyzed in order to find out the cause of no epitaxial growth when the active oxygen supply density is low. The carbon in the film was analyzed using a quadrupole secondary ion mass spectrometer (SIMS). The samples are a CeO ₂ film epitaxially grown under the condition (A) in FIG. 19 and a conductive black thin film sample grown under the condition (C) in FIG. The results of each experiment are shown in FIG.
Ce (result of (A)) and FIG. 23 (result of (C))
The distribution data of C and O in the depth direction are shown. The amount of carbon in the CeO ₂ epitaxial film (A) was about the same as in the SrTiO ₃ substrate, and was below the detection limit. Carbon was clearly detected in the conductive thin film sample (C), and the signal was more than two orders of magnitude higher than that in (A).

Further, with respect to some thin film samples, Ce and C, which are main constituent elements, were measured by Auger electron spectroscopy.
The profile of O in the depth direction was investigated. Considering the specific sensitivity coefficient, the sample (C) contains 14 to 32 at% carbon, which means that the number of C atoms is 0.4 relative to the number of Ce atoms.
It is equivalent to about 1 time. In addition, when the oxygen flow rate in FIG. 21 was 1.25 sccm and the sample was examined by Auger electron spectroscopy, it was found that the carbon concentration in the film was low.
It was about 5 at% and the atomic ratio of C / Ce was about 0.1.
In addition, under the same conditions as the sample (C), a sample (black thin film sample having conductivity) formed by turning off ECR plasma and not activating oxygen was examined by Auger electron spectroscopy. It was The result is shown in FIG. As a result of not irradiating active oxygen during film formation, the carbon concentration in the film was 25
The carbon content was up to 32 at%, and the carbon content was 0.5 to 0.8 times that of C / Ce.

Further, X-ray photoelectron spectroscopy (XPS) analysis was performed. The sample is a film formed under the condition close to (C) in FIG. 19, and is a black thin film sample having conductivity. As a reference sample, the same conditions such as active oxygen conditions and substrate temperature were used, and instead of the gas source, Knudsen.
Evaporation of Ce metal from the cell onto SrTiO ₃ (110) substrate
A CeO ₂ film was prepared. As a result, a colorless and transparent CeO ₂ film having infinite resistance and (111) orientation as seen by X-ray diffraction was obtained. Epitaxial growth is observed by RHEED.
Since the carbon analysis accuracy was low in XPS because the peaks of Ce and C overlap, there is no significant difference in the amount of carbon in the film between the black sample and the reference sample, which have conductivity due to the organometallic gas source. It was The results of examining the chemical bond state of Ce (3d level of Ce) are shown in FIGS. 25 and 26. In the reference sample shown in FIG. 25, a satellite peak attributed to CeO ₂ was detected, whereas in the thin film sample under the conditions close to (C) by the gas source shown in FIG.
A peak close to Ce was observed, and the above satellite peak was hardly detected. It can be said that Ce of the thin film sample under the condition close to (C) has an electronic state close to that of metal and is not completely oxidized. Therefore, together with the results of SIMS and the results of the etching test using an acid described above, it is considered that the state is closer to that of cerium carbide due to the incorporation of carbon, rather than the fact that Ce, which is close to the metallic state, is mixed.

The surface morphology of the film was determined by SEM and FE-SE.
Observed at M. FIG. 27 shows an SEM observation photograph, and FIG. 28 shows F.
The E-SEM observation photograph is shown. 27 (a) and 28
As shown in (a), no clear structure was observed in the case of the epitaxially grown CeO ₂ film (A). On the other hand, as shown in FIGS. 27 (b) and 28 (b),
In the case of a conductive film (C) containing Ce-CO as a main component, irregularities having a grain structure of about 20 nm may be seen. It was found that it was difficult to obtain superconductivity due to the fact that carbon was not diffused and the carbon diffused from the underlayer.

From the above analysis results, it was found that in the film under the conditions greatly deviated from the epitaxial growth conditions (near (C) in FIG. 19), a large amount of carbon was mixed and Ce was not sufficiently oxidized. Therefore, the reason why epitaxial growth does not occur on the low oxygen flow rate side of the one-dot chain line in FIG.
It is considered that this is because carbon and Ce that has not completely oxidized are mixed in the film.

From FIG. 19, it was found that in order to grow epitaxially, it was necessary to increase the oxygen flow rate almost in proportion when the organometallic gas supply density was increased. Here, the flux of the component of each gas is compared. Oxygen flow rate
At 1.25 sccm, the O ₂ molecular flux is approximately 8 × 10.
^-5 [mol m ^-2 s ^-1 ]. In addition, by vacuum-depositing an Ag film on a crystal oscillator type film thickness monitor, oxidizing it with an ECR plasma active oxygen source, and measuring the weight change with the frequency change of the crystal oscillator, the active oxygen flux was measured. It was measured. At this time, the active oxygen that oxidizes Ag is considered to be atomic oxygen. The atomic oxygen flux estimated from this experiment is 1.62 × 10 ⁻⁶ [mol m ⁻² s ⁻¹ ] on the substrate when the oxygen flow rate is 1.25 sccm and the discharge power is 100 W. At this time, C
When the e (dpm) ₃ flux is 1.35 × 10 ^-7 [mol m ^-2 s ^-1 ], epitaxial growth occurs, and the Ce (dpm) ₃ flux is 1.
When it increases to 90 × 10 ^-7 [mol m ^-2 s ^-1 ], epitaxial growth stops.

By the way, 45 moles of O ₂ molecules are required to completely burn 1 mole of Ce (dpm) ₃ . Now, under any of the above Ce (dpm) ₃ flux conditions, a sufficient amount of O ₂ molecule is supplied for complete combustion. Nevertheless, the fact that epitaxial growth may not occur indicates that the active oxygen flux is important. A simple calculation shows that 12 times as much atomic oxygen as Ce (dpm) ₃ causes epitaxial growth, and 8.5 times does not cause epitaxial growth. Evaporate metalorganic YBa ₂
It has been previously reported that when producing Cu ₃ O _7-δ , it is necessary to supply the substrate with active oxygen having a certain density or more to obtain a film with good crystallinity or a film with high T _c. There is. However, it has not been quantitatively discussed. 1 mole
In the reaction process of Ce (dpm) ₃ CeO ₂ and decomposition is epitaxially grown, 0 ₂ molecule is not critical, active oxygen was first found in the present invention that it requires 10 moles or more.

As a result of the experiment, even if the oxygen flow rate was changed,
Further, even if the ECR discharge is stopped, there is no sudden change in the amount of Ce deposited on the substrate regardless of the presence or absence of epitaxial growth. From this fact and the experimental results of the substrate temperature dependence, it is considered that the process of decomposition of Ce (dpm) ₃ and deposition on the substrate is mainly thermal decomposition under the dependence of O ₂ molecules. In this reaction process, Ce
It is considered that (dpm) ₃ is not completely burned, but the ligand is broken. Considering the above analysis results, active oxygen oxidizes and removes carbon deposited on the substrate, and Ce
Contributes to the epitaxial growth by playing the role of completely oxidizing. If so, the above-mentioned evaluation value of the required amount of active oxygen indicates that the order of the amount of carbon deposited on the substrate by the thermal decomposition is about 10 mol per 1 mol of Ce. Therefore, it is Ce (dpm) (= C where two dpm ligands are displaced that the raw material decomposes and is first adsorbed on the substrate.
₁₁ H ₁₉ O ₂ Ce).

As a result of conducting many experiments under various conditions, (A) epitaxial growth was carried out when the ratio of the active oxygen supply density to the molecular supply density of the β-diketone complex of Ce on the substrate was 10 times or more. obtained good crystallinity CeO ₂ film is, (C) when the ratio of the active oxygen supply density to molecular supply density of β- diketone complex of Ce is less than 4 times, amorphous or microcrystalline having conductivity A Ce-CO film composed of polycrystals of is obtained, and in the region between (B), (A) and (C), a CeO ₂ film with poor crystallinity and easy to be etched by acid or ion beam is obtained. I found out. The reason for this is considered as follows. The Ce (dpm) ₃ molecule from the nozzle reaches the substrate with almost no collision with other molecules,
The molecules are warmed by the heated substrate. In the presence of O ₂ molecule
When the Ce (dpm) ₃ molecule is heated to 300 ° C or higher, the ligand is desorbed immediately, so that it is first adsorbed on the substrate in the form of Ce (dpm), which is relatively safe. If the film growth is continued as it is, (dpm)
A part of C contained in is retained in the membrane.
At the same time, due to H contained in (dpm), C that is not completely oxidized
e remains in the film. This state is (C).

In the following, referring to FIG. 8, Ce (dpm)
Consider one molecule. In (dpm), adjacent to Ce, a total of four bonds of two CO bonds and two CC bonds form a conjugated bond. When four oxygen radicals come here, the conjugated bonds are broken by the radical reaction. Therefore, the amount of carbon taken into the film is drastically reduced. However, in this state, not all the carbon contained in (dpm) has been burned, so the film contains
Less than 1 at% carbon remains. As a result, although CeO ₂ is formed, its crystallinity is poor and epitaxial growth does not occur. This state is (B), and since the crystallinity is poor, a thin film that is easily etched by an acid or an ion beam can be obtained. When 11 oxygen radicals come, they are included in (dpm)
A radical reaction can occur with all 11 carbons, and almost all carbon escapes into the gas phase and does not remain in the film. As a result, a CeO ₂ film having good crystallinity is epitaxially grown. The state is (A).

Example 2 Next, an example will be described in which the ratio of the supply density of active oxygen to the molecule supply density of the β-diketone complex of Ce on the substrate was spatially changed. In order to investigate its effectiveness, first, the mean free path of each gas molecule near the substrate is investigated. Gas X
The respective mean free paths λ _X and λ _Y in the case where there is a very small amount of gas Y than X and X are represented by the following equations, respectively.

[0100]

(Equation 6)

(Equation 7) Now, assuming that X is O ₂ and Y is Ce (dpm) ₃ , the diameter of O ₂ molecule d _X = 3.7 × 10 ^-10 m, the experimental diameter of Ce (dpm) ₃ d _Y = 1 × 1
0 ^-9 m, oxygen distribution density n around the substrate used in Example 1
_X = 4.5 to 14 × 10 ¹⁷ m ⁻³ , the molecular density n of Ce (dpm) ₃ around the substrate obtained from the intensity of the organometallic molecular beam used in Example 1
^{_{Y = 6.4~23 × 10 14 m -3}} , a molecular weight of _{O 2 M X = 32, Ce} (dp
Substitute the molecular weight M _Y of m) ₃ = 689.9. As a result, the mean free path of oxygen electrons λ _X = 1200 to 3700 mm and the mean free path of Ce (dpm) ₃ molecules λ _Y = 100 to 320 mm are obtained. λ _X is sufficiently longer than the distance between the active oxygen source and the substrate (123 mm in the case of Example 1). λ _Y is sufficiently longer than the distance between the gas source nozzle and the substrate (49 mm in the case of Example 1). Therefore, in this embodiment, after the O ₂ molecule, the active oxygen and the organometallic molecule have come out of the nozzle hole into the film forming chamber, they directly reach the substrate with almost no collision with other molecules. Therefore, the method of spatially changing the ratio of the supply density of active oxygen to the molecule supply density of the organometallic complex described below works very effectively.

The film forming method of SJ Duray et al.
In the case of the film formation method of K. Kanehori et al., The oxygen pressure in the film formation chamber is 1.3.
It was as high as × 10 _-2 to 1.3 Pa. Using this pressure, the other conditions are the same as above, and the mean free path is determined. Collisions between molecules frequently occur indoors, and straightness cannot be maintained. Therefore, in these conventional examples, the method of spatially changing the ratio of the molecular supply densities does not work effectively.

FIG. 29 shows an example in which an ECR plasma active oxygen source is used. A microwave stripline mask 67 was prepared from a stainless steel plate having a thickness of 1 mm, and the mask 67 was placed between the active oxygen source (ECR gun 58) and the substrate 60. In order to obtain a parallel active oxygen beam as much as possible, the outlet of the active oxygen source was a nozzle with a large number of cylindrical holes arranged 20 times longer than the radius. When a thin film was formed under the same conditions as in Example 1, (A) a CeO ₂ epitaxial film having good crystallinity was obtained on the substrate 60 corresponding to the hole of the mask 67. On the substrate 60 shielded by the mask, there is no active oxygen and only O ₂ molecules drift, so that a conductive film containing (C) Ce, C and O as main components is obtained. The film surface was rough.

Further, after the same film formation is performed using the mask 67, the mask 67 is moved, and the Knudsen cells 52, 53, 54, 55, 5 are continuously moved without breaking the vacuum.
6 was used to deposit a (Pb ₂ Cu) Sr ₂ (Dy, Ca) Cu ₂ O _{8 + δ} superconductor film. As a result, for example, the microwave passive element shown in FIG. 3 could be manufactured. Superconducting film is YB
It may be a ₂ Cu ₃ O _7-δ .

FIG. 30 shows an example in which the substrate is scanned with a thinly focused ozone beam. Using the pure ozone source described above, the ozone beam nozzle 68 was manufactured so that the effective length of the orifice having a diameter of 0.1 mm was 5 mm or more. The ozone beam nozzle 68 is provided at the tip of the flexible tube. The direction of the ozone beam nozzle 68 was automatically changed during film formation by driving a motor by a predetermined program. When the substrate 60 was scanned with the ozone beam emitted from the ozone beam nozzle 68, the ratio of the ozone supply density to the molecule supply density of the organometallic complex was increased 20 times as an average value within a fixed time (for example, 1 minute). (A) CeO ₂ film with good crystallinity was epitaxially grown in the place where the ratio of ozone supply density to the molecular supply density of the organometallic complex was 6 times, and (B) the crystallinity was poor. Easily etched C
An eO ₂ film was formed. In addition, a fixed time (eg 1 minute)
The Ce-CO resistance film was formed at the place where the ratio of the ozone supply density to the molecular supply density of the organometallic complex doubled as the average value in the inside. Thus, the thin film layer 26 having the insulating layer for separation 23 and the resistance film 24 in FIG. 2 could be manufactured.

When fine patterning is performed, it is desirable to apply the following method. That is,
If the ratio of the active oxygen supply density to the molecule supply density of the organometallic complex is spatially changed using a focused ion beam device (FIB), fine patterning up to submicron size can be easily performed by the method of the present invention. be able to. Example 3 An example in which a high dielectric constant material is deposited for a silicon device will be described. In the film forming apparatus shown in FIG. 7, Sr and Ba are vaporized from the Knudsen cell, Ti (dpm) ₄ raw material is put into the organometallic gas source source 64, and Ba _0.5 Sr _{0.5 is} deposited on the Si substrate with the thermal oxide film. TiO ₃ was prepared. At that time, only about 5 atomic layers of Sr was deposited on the substrate heated to 600 ° C while irradiating with active oxygen, and then the β-diketone complex of Ti and Ba were deposited.
By depositing Sr and Sr on the substrate, Ba _0.5 Sr _0.5 TiO ₃ with perovskite structure could be epitaxially grown on the Si substrate with thermal oxide film.

Using the metal mask described in Example 2, a portion (A) in which the ratio of the supply density of active oxygen to the molecule supply density of the β-diketone complex to the substrate was set to 10 times or more, and the active oxygen was removed by the mask I made a part (B) that was about 6 times as blocked. As a result, in (A), Ba _0.5 Sr _0.5 Ti with good crystallinity is obtained.
O ₃ was epitaxially grown, and in the portion (B), a Ba _0.5 Sr _0.5 TiO _{3 -δ} polycrystal having poor crystallinity was grown.
In the portion (B), carbon was mixed in the film in an amount of 0.01 at% or more, and the average valence of Ti was 3.99 to 3.7. As a result of etching this thin film sample with hydrochloric acid, only the portion (B) was etched and the portion (A) and the substrate were not etched. That is, patterned Ba with good crystallinity
_{A 0.5} Sr _0.5 TiO ₃ film was obtained.

The thin film sample deposited by the above method is
As a result of plasma etching using a gas of Ar85% -CF ₄ 15%, the etching mechanism was mainly sputter etching by ions rather than chemical etching. The etching rate of the portion (B), which was a polycrystalline body with poor crystallinity, was 20 times or more higher than that of the epitaxially grown portion (A) with good crystallinity. The etching rate of the portion (B) was 30 times or more as high as that of SiO ₂ . Therefore, after etching, the high dielectric constant thin film Ba _0.5 Sr _0.5 TiO ₃ according to the shape of the holes of the metal mask remained on the Si substrate.

As described above, according to this example, a dielectric film which can be easily patterned without the resist coating, exposing and developing steps was obtained. In the above example, an example of a Ba _0.5 Sr _0.5 TiO ₃ single layer thin film was described, but in addition to this, the advantage that the MONBE method of the present invention facilitates stacking for each atomic layer makes it possible to reduce the dielectric constant even if it is thin ₃ [4u
nit] / BaTiO ₃ [4unit] or (Sr _0.3 Ba _0.7 ) TiO ₃ [4unit]
/ (Ca _0.52 Sr _0.47 ) TiO ₃ [4unit] strained superlattice (total film thickness
10 nm). The substrate is scanned with a thinly focused ozone beam while controlling the shutter to deposit each molecular layer, and (A) the epitaxially grown portion with good crystallinity and (B) the polycrystalline portion with poor crystallinity are the same thin film. Made in layers. As a result of performing Ar ion milling, the etching rate of the portion (B) was 20 times or more higher than that of the portion (A). Thus, the method of the present invention can be applied to various dielectric materials.

Example 4 Next, an example of an oxide magnetic thin film will be described. Figure 9
The same source of organometallic gas source as in the above was attached to the three MBE units, and La (dpm) ₃ , Sr (dpm) ₂ , M
I entered n (dpm) ₃ . By supplying organometallic molecules toward the substrate from three nozzles and simultaneously supplying active oxygen, a La _1-x Sr _x MnO ₃ thin film having a perovskite crystal structure was prepared. A MgO (100) surface was used as the substrate, and it was heated to 650 ° C during film formation. For La _0.825 Sr _0.175 MnO ₃ sample with a film thickness of 200 nm
When the magnetoresistive effect was measured by applying a magnetic field of 6 T, 280
A negative reluctance of 80% was obtained at K.

This giant magnetoresistive effect is expected to be applied to a read head for a high density magnetic disk, but for that purpose, a thin film must be patterned to a size of several microns. Here, an example of the head shape is shown in FIG.
In FIG. 31, 69 is an MgO substrate, and a large number of magnetic thin film heads 70 patterned into a predetermined shape are formed on the MgO substrate 69. In addition, the magnetic thin film 70
An electrode film 71 is formed on the top, as shown in FIG.

In the manufacturing process of the head as described above, it is necessary to pattern and cut out a large number of heads 70 from the magnetic thin film deposited on the MgO substrate 69 of 20 × 20 mm. Conventionally, in the etching of perovskite type magnetic thin film, it is difficult to obtain selectivity with MgO substrate,
This patterning process has been extremely difficult. In addition, there is a problem that the magnetic characteristics of the film change in a complicated lithography process and patterning process.

In this example, a part (A) in which the ratio of the supply density of active oxygen to the molecule supply density of the organometallic compound was 10 times or more, and a part (B) in which the ratio was about 5 times were prepared. As a result of performing Ar ion milling, the etching rate of the portion (B) was 30 times or more higher than that of the portion (A). As a result, the pattern of the magnetic thin film head 70 on the MgO substrate 69 shown in FIG. 31 could be produced only by Ar ion milling without performing resist coating, exposing and developing steps. Since this is a simple process, there was no change in magnetic properties. When the part (C) in which the ratio of the supply density of active oxygen to the supply density of molecules of the organometallic complex is less than 4 times is prepared, a resistive thin film containing carbon at 1 at% or more and having no magnetoresistive effect can be obtained. It was This portion can have a function as a shunt resistance that does not depend on the magnetic field.

The magnetic thin film is preferably a perovskite type oxide containing a transition metal element as a main element. Among them, especially (La, A) BO _3-δ and (Pr, A) BO _3-δ (A is Ca,
At least one element selected from Sr, Ba and Pb, B
Is desirable because at least one element selected from Mn and Co) has a large magnetoresistive effect.

The embodiments of the present invention have been described in detail above. Next, reference examples in which a flat oxide thin film is formed by the MONBE method will be described.

First, using the MBE apparatus shown in FIG.
An example of manufacturing a laminated Josephson junction will be described.
A SrTiO ₃ (100) substrate was heated to 700 ° C., and a thin film was grown while supplying 3.3 sccm of oxygen gas activated by 100 W ECR discharge. The oxygen pressure in the film forming chamber 51 at that time is
It was 5.2 × 10 ⁻³ Pa as measured by the ion gauge 61. Pb
Knudsen cell 52 with syrup at 650 ℃, Knudsen cell 53 with Sr at 477 ℃, Knudsen cell 54 with Ca at 525 ℃, Knudsen cell 55 with Dy at 980 ℃. , Knudsen cell 56 containing Cu is 10
It was set to 51 ° C. Sr, Ca, Dy and Cu are all evaporation rates for one atomic layer deposition in 30 seconds. Ce (dpm) ₃ was placed in the raw material container 641 of the gas source source 64 and kept at 183 ° C.
At this temperature, one atomic layer is deposited in 1 minute.

First, as the lower electrode, (Pb ₂ Cu) Sr ₂ (D
y, Ca) Cu ₂ O _{8 + δ} superconductor film was deposited. First, two atomic layers of Sr are deposited on the substrate, and then Cu (30se
c), Dy (15sec), Ca (15sec), Cu (30sec), Sr (30se
c), Pb (45sec), Cu (30sec), Pb (45sec), Sr (30sec)
2 units of cells were deposited in this order. This is necessary for the layered growth without releasing the impurity phase in the initial stage of growth. Next, Cu (30sec), Dy (15sec), Ca (15sec), Cu (30se
c), Sr + Pb (30sec), Pb (7.5sec), Pb + Cu (15sec), Pb (7.5
sec) and Pb + Sr (30 sec) in this order, 18 unit cells were deposited. Here, by depositing Pb at the same time as Sr or Cu, the incorporation rate of Pb into the film can be increased. In addition, [SrO-PbO
-Cu-PbO-SrO] by depositing Cu contained in the charge reservoir block layer of about half of the stoichiometric composition,
It was found that the precipitation of Cu ₂ O on the growth surface during the block growth was suppressed and the layered growth was facilitated. This effect is particularly effective when the oxygen partial pressure in the film forming chamber is as high as 5.2 × 10 ^-3 Pa, and Cu is stoichiometric when the oxygen partial pressure in the film forming chamber is as low as 1.7 × 10 ^-3 Pa. Layered growth can be achieved by depositing only the composition.

Next, the intermediate layer material was deposited. The intermediate layer material is a layered copper oxide (chemical formula:
(Pb ₂ Cu) Sr ₂ (Dy, Ce) ₇ Cu ₂ O _{8 + δ} ). this
When one unit胞分deposition, multiple fluorite block is an ideal insulating layer, Cooper pairs tunnel from CuO ₂ plane which is located adjacent to and below the multi-fluorite block to CuO ₂ plane located in the center It becomes an S / I / S type Josephson junction. After the above shutter sequence, Cu (30se
c: CuO ₂ surface) and Dy (15 sec) were deposited. afterwards,
Six layers of CeO ₂ were deposited using an organometallic gas source.
After that, Dy (15 sec), Cu (30 sec: equivalent to CuO ₂ surface), Sr + P
b (30sec), Pb (7.5sec), Pb + Cu (15sec), Pb (7.5sec),
Pb + Sr (30 sec) was deposited.

Next, as an upper electrode, (Pb ₂ Cu) Sr ₂ (Dy,
Ca) Cu ₂ O _{8 + δ} superconductor film was deposited. Specifically, C
u (30sec), Dy (15sec), Ca (15sec), Cu (30sec), Sr + P
b (30sec), Pb (7.5sec), Pb + Cu (15sec), Pb (7.5sec), Pb
20 unit cells were deposited in the order of + Sr (30 sec). As a result of the above thin film growth, a laminated Josephson junction was obtained. That is, the MONBE method according to the present invention is suitable for producing an electronic device in which a composite oxide is laminated and evaporation from a Knudsen cell can be used at the same time.

As a result of observing the manufacturing process of this laminated junction in detail by RHEED, it was confirmed that CeO ₂ was produced using an organometallic gas source.
It was found that the flatness of the growth surface was slightly compromised during the deposition of 6 layers. In the deposition of the intermediate layer material, when 12 layers were deposited as a trial for the case where 6 layers of CeO ₂ were deposited using an organometallic gas source, RHEED was obtained after the 10th layer.
It was found that the pattern changed to a spot shape (indicating that {111} facets were formed) or a ring shape (indicating that it was in a polycrystalline state). As its precursor, C
It was found that the surface flatness gradually diminished during the deposition of 6 layers of eO ₂ . So Ce from the gas source
Deposition and Dy deposition from Knudsen cell at the same time, Ce
_{When 0.8} Dy _0.2 O _y was changed to deposit 7 layers, layered growth became easier. Similar effects were obtained by using Pb, Cu, or Eu instead of Dy. The reason is as described in the first embodiment.

In order to grow flat and obtain an S / I / S type junction, the shutter sequence for interlayer material deposition is:
Cu (30sec: Corresponds to CuO ₂ surface), 7 layers of Ce _0.8 Dy _0.2 O _y are deposited simultaneously using an organometallic gas source and Knudsen cell, Cu (30sec: Corresponds to CuO ₂ surface), Sr + Pb ( 30sec), Pb
It has been found that (7.5 sec), Pb + Cu (15 sec), Pb (7.5 sec), and Pb + Sr (30 sec) are effective. This laminated junction is vertically symmetrical and has the following laminated structure. There is in the center as an insulating layer multiplexing fluorite block (thickness 1.7 nm), Cooper pairs are tunnel from CeO ₂ surface positioned adjacent to and below the CeO ₂ surface. On the outside of [SrO-PbO-Cu-PbO-SrO]
There is a charge reservoir block layer, and the block layer is shared on the outside (Pb ₂ Cu) Sr ₂ (Dy, Ca) ₇ Cu
₂ O _{8 + δ} superconductors exist as upper and lower electrodes.

Next, a CeO ₂ thin film flat at the atomic layer level was formed.
An example prepared on the (100) plane of an SrTiO ₃ substrate will be described. CeO ₂ is used as an insulating layer for the S / I / S type junction, as well as a buffer material between the thin film and the substrate, and an insulating material between the superconducting wiring and the ground plane.

This example was carried out at a substrate temperature of 700 ° C.
Using a metal-organic gas source, deposit a CeO ₂ thin film at 0.3 nm / min.
The deposition rate was 3.6 nm. The film forming conditions are as follows: the raw material heating oven temperature is 184 ° C, and the oxygen gas is 4.16 cm ³ / min.
The film was formed by irradiating the substrate by activating the ECR discharge and irradiating the substrate.

RHEE after the growth of CeO ₂ is completed
The D diffraction pattern is shown in FIG. Transmission spots in the form of a triangular lattice were obtained, indicating that CeO ₂ was grown in islands. C
The most stable surface of eO ₂ is the {111} plane, so SrTiO ₃ (10
When epitaxially grown on the (0) plane, island-like growth occurs with the {111} facet as the outermost surface.

In order to flatten the island-grown CeO ₂ thin film, it is effective to attach an element other than Ce to the crystal surface and change the most stable crystal surface from the {111} plane to the {100} plane. Is. Therefore, after the growth of CeO ₂ is completed, elements other than Ce such as Pb or Cu, Eu, and Dy are attached to the surface, and then the substrate temperature is lowered to 300 to 650 ° C, preferably 500 to 600 ° C. It was held and annealed at a temperature lower than the growth temperature. As a result, as shown in FIG.
In the HEED diffraction pattern, the spot became weak and changed to a streak shape. It has Pb, Cu, Eu, and
Elements other than Ce such as Dy diffuse near the surface of the CeO ₂ crystal,
As a result, {111} face is not the most stable surface. By annealing at a low temperature, oxygen defects are reduced and C
It is possible to stabilize the fluorite structure, which is the crystal structure of eO ₂ . The different elements other than Ce attached to the surface exist in the form of solid solution near the surface of the CeO ₂ crystal.

During the deposition of CeO ₂ , Pb or Cu, E
Even if an element other than Ce such as u or Dy is supplied, a thin film having a flat surface can be produced. However, when CeO ₂ is used as the insulating layer, it is easy to form a conductor by mixing different elements, and therefore, as described above. Further, a method of forming a solid solution with a different element only in the surface layer is advantageous.

Next, another specific example of producing a flat insulating layer containing Ce will be described.

First, as the lower electrode, (Pb ₂ Cu) Sr ₂ (Eu,
A Ca) Cu ₂ O _{8 + δ} superconductor film was deposited at a substrate temperature of 700 ℃. This method is similar to the method described in Example 5.
Then, as an intermediate layer material, (Pb ₂ Cu) Sr ₂ (Eu, Ce) ₇ Cu
₂ O _{8 + δ} was deposited. Specifically, at a substrate temperature of 700 ° C., Cu (30 sec: equivalent to CuO ₂ surface) and Eu (15 sec) were deposited, and then 6 layers of CeO ₂ were deposited using an organometallic gas source. Next, Eu (15 sec) and Cu (30 sec: equivalent to CuO ₂ surface) are deposited, and then 300 to 650 ° C, preferably 500 to 60 ° C.
The substrate temperature was lowered to 0 ° C. and kept at that temperature for 30 minutes for low temperature annealing. Meanwhile, CeO ₂ is flattened by the principle shown in Example 6.

After that, in order to manufacture the upper electrode, the substrate temperature is set to 650 ° C. which is lower than the temperature at which the lower electrode was grown. If the substrate temperature is raised to 700 ° C at which the lower electrode is deposited, oxygen on the outermost surface is desorbed, and the dissimilar elements Eu and Cu, which are solid-soluted on the outermost surface, begin to precipitate and CeO ₂ {1
11} Crystal grains with the facets on the surface grow and the surface irregularities become remarkable. Sr + Pb (30sec), Pb (7.5sec), Pb + Cu (15sec), Pb (7.5se) immediately after the substrate temperature reaches 650 ℃.
c), Pb + Sr (30 sec) is deposited.

Thereafter, the lower electrode was formed at the substrate temperature.
Raise to 700 ℃. After growing one unit cell of the intermediate layer material, CeO ₂ {111} is no longer present even if the substrate temperature is raised.
Crystal grains with facets on the surface do not grow. in addition
(Pb ₂ Cu) Sr ₂ (Eu, Ca) Cu ₂ O _{8 + δ} By depositing a superconducting film, the S /
I / S type junctions can be made. Note that similar crystal growth can be performed by using Dy, which is another rare earth element, instead of Eu.

[0130]

As described above, according to the manufacturing method of the present invention, for example, (A)
Epitaxially grown oxide thin film with good crystallinity,
(B) An oxide thin film having poor crystallinity and easily etched,
(C) Two or more kinds of thin films having different electrical characteristics and crystallinity such as a conductive thin film containing 10 at% or more of carbon can be formed in an arbitrary plane shape. As a result, the lithography process in the manufacturing process of superconducting elements such as Josephson integrated circuits and passive microwave elements, semiconductor elements using dielectric thin films, oxide thin film elements such as magnetoresistive elements can be simplified, and oxides can be efficiently used. It becomes possible to fabricate a thin film element and prevent deterioration of characteristics such as superconducting characteristics and magnetic characteristics in the lithography process. Further, according to the superconducting element of the present invention, it is possible to prevent deterioration of the superconducting characteristics of the superconducting conductive electrode and the like around the contact hole.

[Brief description of drawings]

FIG. 1 is a diagram showing conditions under which three types of thin films having different properties can be formed by the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a Josephson integrated circuit of an embodiment manufactured by applying the manufacturing method of the present invention.

FIG. 3 is a cross-sectional view showing a structure of a passive microwave device according to another embodiment manufactured by applying the manufacturing method of the present invention.

FIG. 4 is a diagram showing a manufacturing process of another passive microwave element to which the manufacturing method of the present invention is applied.

FIG. 5 is a diagram showing a structure of a passive microwave device according to still another embodiment manufactured by applying the manufacturing method of the present invention.

FIG. 6 is a diagram showing a manufacturing process of a bi-epitaxial Josephson junction to which the manufacturing method of the present invention is applied.

FIG. 7 is a diagram showing a configuration of an MBE device used in an example of the present invention.

FIG. 8 is a structural formula of an example of the organometallic raw material used in the examples of the present invention.

9 is a diagram showing in detail the vicinity of an organometallic gas source source of the MBE device shown in FIG.

FIG. 10 is a diagram showing a positional relationship between a gas source nozzle and a substrate in Example 1 of the present invention.

FIG. 11: CeO on the substrate in Example 1 of the present invention
FIG. ₂ is a diagram showing a deposition rate distribution.

FIG. 12 is a diagram showing a material temperature dependency of an organometallic gas supply rate and a CeO ₂ deposition rate in Example 1 of the present invention.

FIG. 13 is a diagram showing the substrate temperature dependence of the CeO ₂ deposition rate in Example 1 of the present invention.

FIG. 14 is a diagram showing the substrate temperature dependence of the X-ray diffraction intensity of the thin film in Example 1 of the present invention.

FIG. 15 is a diagram showing an example of an X-ray diffraction pattern of a thin film according to Example 1 of the present invention.

FIG. 16 is a diagram showing another example of the X-ray diffraction pattern of the thin film according to Example 1 of the present invention.

FIG. 17 is a diagram showing still another example of the X-ray diffraction pattern of the thin film according to Example 1 of the present invention.

FIG. 18: RHEED of a thin film according to Example 1 of the present invention
It is a photograph showing a diffraction pattern.

FIG. 19 is a diagram showing conditions of an oxygen flow rate and an organometallic gas supply rate for epitaxial growth in Example 1 of the present invention.

FIG. 20 is a diagram showing an X-ray diffraction result of a thin film according to Example 1 of the present invention.

FIG. 21 is a diagram showing an X-ray diffraction result of a thin film under another condition of Example 1 of the present invention.

FIG. 22 is a diagram showing SIMS analysis results of a thin film according to Example 1 of the present invention.

FIG. 23: SIM of another thin film according to Example 1 of the present invention
It is a figure which shows the analysis result by S.

FIG. 24 is a diagram showing the results of Auger electron spectroscopy analysis of a thin film according to Example 1 of the present invention.

FIG. 25 is a diagram showing an XPS analysis result of a reference sample thin film in Example 1 of the present invention.

FIG. 26 is a diagram showing a result of XPS analysis of a thin film according to Example 1 of the present invention.

FIG. 27 is an SEM of the thin film surface according to Example 1 of the present invention.
It is a photograph showing an image.

FIG. 28: FES of thin film surface according to Example 1 of the present invention
It is a photograph showing an EM image.

FIG. 29 is a diagram showing an example of the configuration of an apparatus for spatially changing the ratio of the supply density of active oxygen to the molecule supply density of an organometallic compound in Example 2 of the present invention.

FIG. 30 is a diagram showing another structural example of an apparatus for spatially changing the ratio of the supply density of active oxygen to the molecule supply density of an organometallic compound in Example 2 of the present invention.

FIG. 31 is a diagram showing a main configuration of a read head for a magnetic disk according to a fourth embodiment of the present invention.

32 is an enlarged perspective view of a magnetic thin film head portion of the magnetic disk read head shown in FIG. 31. FIG.

FIG. 33 is a photograph showing a RHEED diffraction pattern of a thin film according to a reference example.

FIG. 34 is a cross-sectional view showing one structural example of a conventional Josephson integrated circuit.

FIG. 35 is a diagram showing a structural example of a conventional passive microwave element.

FIG. 36 is a cross-sectional view showing a manufacturing process of a conventional bi-epitaxial Josephson junction.

[Explanation of symbols]

21, 31, 46 ... Substrate 22, 27, 29 ... Superconducting layer 23 ... Separation insulating layer 24 ... Resistive film 25 ... Contact holes 26, 34, 35, 38 ... Formed once Thin film layer 30 ... Josephson junction 32, 39, 48 ... Epitaxial insulating layer with good crystallinity 33 ... Conductive layer containing C 40, 49 ... Insulating layer with poor crystallinity and easy to dissolve in acid 41 , 43, 44, 50 ... Oxide superconducting film showing superconducting properties 42 ... Portion not showing superconducting properties

Claims (5)

[Claims] 1. A method for producing an oxide thin film element, comprising the step of producing an oxide thin film by supplying an organic metal compound and active oxygen to a substrate in a vacuum chamber, wherein the oxide thin film producing step comprises: A method of manufacturing an oxide thin film element, characterized in that the ratio of the molecule supply density of the organometallic compound and the supply density of the active oxygen on the substrate is spatially changed. 2. The method of manufacturing an oxide thin film element according to claim 1, wherein an oxide thin film having good crystallinity and being epitaxially grown, an oxide thin film having poor crystallinity and being easily etched in the step of producing the oxide thin film, A method for producing an oxide thin film element, which comprises producing a thin film having two or more kinds of portions selected from a conductive thin film containing carbon at 10 at% or more. 3. A process of supplying a β-diketone complex of Ce and active oxygen to a substrate to produce an oxide thin film of Ce in a vacuum chamber, and laminating a superconductor thin film on the oxide thin film of Ce. In the method for producing a superconducting element having a step of forming, in the step of producing an oxide thin film of Ce, the ratio of the molecular supply density of the β-diketone complex of Ce on the substrate and the supply density of the active oxygen is set. A method for manufacturing a superconducting element, which is characterized by spatially changing. 4. A method of manufacturing a superconducting device according to claim 3, wherein, in the manufacturing process of the oxide film of the Ce, CeO ₂ insulating film crystallinity was good epitaxial growth, crystallinity is poor etched easily CeO ₂ insulating film , And Ce and C with conductivity
A method for producing a superconducting element, which comprises producing a thin film having two or more kinds of moieties selected from the thin films containing O and O as main components. 5. A superconducting element comprising a superconducting layer and an insulating layer formed in contact with the superconducting layer, wherein the insulating layer is an oxide containing at least one element selected from Al, Si and rare earth elements. 1. A superconducting element comprising a material crystal and containing 1 at% or more of carbon in the peripheral portion of the insulating layer in contact with the superconducting layer.