JP3286127B2 - SOI device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a single crystal Si substrate / insulating layer / Si film structure.
icon on Insulator) The present invention relates to a device and a manufacturing method thereof.

[0002]

2. Description of the Related Art Along with recent advances in semiconductor technology, a number of semiconductor devices and methods for manufacturing the same have been proposed which enable high integration.

Hitherto, an SOS (Silicon on Sapphire) structure has been used to form a semiconductor element on an insulating substrate. This is a technique for forming a semiconductor thin film on a sapphire single crystal substrate.

However, in this technique, when a semiconductor thin film is formed, aluminum and oxygen, which are part of the composition of sapphire, are taken into the semiconductor thin film and may deteriorate the electrical characteristics of the semiconductor thin film as impurities. Was. Also, a semiconductor thin film is epitaxially grown,
When trying to obtain a high-quality Si film, the lattice constant of Si and the sapphire of the substrate do not match, a large number of defects are introduced, and the crystallinity of the semiconductor thin film deteriorates. further,
Sapphire substrates were expensive and unsuitable for mass production of devices.

In order to avoid the problem of using sapphire as a substrate, Japanese Patent Application Laid-Open Nos. 63-15442, 6-97401, 2-5567 and 6-85264 disclose the method. There has been proposed an SOI (Silicon on Insulator) structure in which an insulating layer is formed on a Si single crystal substrate, and a Si semiconductor layer as a functional layer is formed thereon.

This SOI structure enables high integration by fabricating a semiconductor element in a Si single crystal substrate on which an integrated circuit is formed and a semiconductor thin film formed thereon via an insulating layer. . In general, as LSIs become more highly integrated, miniaturization of wiring is inevitable. In this wiring, a CR distributed constant circuit is composed of the wiring resistance, the capacitance between the wirings, the capacitance between the wiring and the substrate, and the capacitance of the transistor itself, which causes a problem of signal delay and attenuation. In the case of a semiconductor element formed over an insulating substrate, since the semiconductor element is formed over an insulating substrate, the capacitance between the wiring and the substrate can be mainly reduced, and high speed operation can be achieved.

The SOI structure has a MOS structure.
FE using a structure or a semiconductor-specific structure such as a pn connection
By providing a T, a CMOS transistor, a bipolar transistor, and the like, an SOI device such as a display device, a high-voltage device, a three-dimensional circuit element, or a solar cell can be realized.

[0008]

However, in the SOI structure disclosed in each of the above patent publications, it is considered that the quality of the insulating layer used, that is, mainly the crystallinity and surface properties are not sufficient, and S formed thereon
It is presumed that it would be difficult to sufficiently bring out the properties of the functional layer by the i-film. Incidentally, the above-mentioned Japanese Patent Application Laid-Open No. 63-1544
Japanese Patent Application Laid-open No. 2 (1994) discloses a technique for forming a Si film on a stabilized zirconia single crystal film formed on a Si single crystal substrate. This is a method using a commonly used oxide formation method, and epitaxial growth is possible, but a stabilized zirconia film having high crystallinity, high surface flatness, and excellent insulating properties cannot be obtained. For device application, it is necessary to realize a thin film having high crystallinity, high surface flatness, and excellent insulating properties.

Further, the Si film formed on the stabilized zirconia single crystal film is also an epitaxial film. However, since the crystallinity and surface flatness of the stabilized zirconia film are not good, it is used as a functional layer. At this time, it is considered that the crystallinity of the Si film is poor, the interface between the stabilized zirconia / S is disturbed, and the insulating properties of the stabilized zirconia film are insufficient, so that the semiconductor characteristics of the Si film cannot be sufficiently brought out.

[0010] In view of the above, an object of the present invention is to provide an SOI device and a method of manufacturing the same that enable high reliability by using a high-quality insulating layer.

[0011]

This and other objects are achieved by the present invention which is defined below as (1) to (15). (1) Si single crystal substrate, zirconium oxide formed as an insulating layer or zirconium oxide stabilized with rare earth metal (including Y) formed on the Si single crystal substrate, and formed on this epitaxial film The composition of zirconium oxide or zirconium oxide stabilized with rare earth metal contains 93 mol% or more of Zr in terms of only the constituent elements except oxygen, and the (002) plane of the epitaxial film. Or (11
1) The half width of the rocking curve of reflection of the surface is 1.5 ° or less, and at least 8% of the surface of the epitaxial film
0% indicates that the ten-point average roughness _Rz at a reference length of 500 nm is 2 nm.
An SOI device that is: (2) The SOI device according to (1), which has a thin film transistor structure in which a gate electrode is formed on the Si film via a gate insulating film. (3) The SOI device according to (1) or (2), wherein the Si film is made of epitaxial Si. (4) The SOI device according to (1) or (2), wherein the Si film is made of polycrystalline Si. (5) The SOI device according to (1) or (2), wherein the Si film is made of amorphous Si. (6) As the Si single crystal substrate, the substrate surface is
The above (1) using a Si surface-treated substrate having a 1 × 1 surface structure formed by Zr metal or Zr metal and at least one rare earth metal (including Y) and oxygen.
The SOI device according to any one of (1) to (5). (7) The SOI device according to any one of (1) to (6) above, wherein a Si single crystal is used as the Si single crystal substrate so that the (100) plane or the (111) plane becomes the substrate surface. (8) The method for manufacturing an SOI device according to claim 1, comprising a Si single crystal substrate, an insulating layer formed on the Si single crystal substrate, and a Si film formed on the insulating layer. Single crystal substrate surface by heating Si single crystal substrate, introducing oxidizing gas into vacuum layer, and evaporating evaporation source consisting only of Zr or a metal or alloy of Zr and at least one rare earth metal (including Y) And the oxide thin film is epitaxially grown on the substrate surface of the single crystal substrate to obtain a composition Zr _{1 -x} R _x O ₂ -δ (where R
Is a rare earth metal containing Y, and x = 0 to 0.75. Δ is 0 to 0.5. A) forming a single orientation epitaxial film and using the same as the insulating layer; (9) As the Si single crystal substrate, the substrate surface is
Zr or Zr and at least one rare earth metal (Y
SOI using the Si surface-treated substrate having a 1 × 1 surface structure formed by oxygen and oxygen.
Device manufacturing method. (10) As the Si surface-treated substrate, a 0.2-10 nm Si oxide layer is formed on the surface of the substrate, and thereafter, the substrate temperature is set at 600-1200 ° C., and oxidation is performed in the vacuum chamber. By introducing a reactive gas, at least the atmosphere near the substrate is set to 1 × 10 ⁻⁴ to 1 × 10 ⁻¹ Torr, and in this state, the surface of the substrate on which the Si oxide layer is formed is
The method for producing an SOI device according to the above (8) or (9), wherein Zr or Zr and at least one rare earth metal (including Y) are supplied by evaporation and a pretreated Si single crystal substrate is used. (11) When forming the Si oxide, the Si single crystal substrate is placed in a vacuum chamber into which an oxidizing gas has been introduced in a range of 300 to 700.
The method for manufacturing an SOI device according to the above (10), wherein the SOI device is formed by heating to a temperature of 0 ° C. and setting the oxygen partial pressure of an atmosphere in a vacuum chamber at least near the substrate to 1 × 10 ⁻⁴ Torr or more. (12) As the Si single crystal substrate, a Si single crystal is
SOI according to any of (8) to (11) above, wherein the (100) plane or the (111) plane is used as the substrate surface.
Device manufacturing method. (13) An oxidizing gas is sprayed from the vicinity of the surface of the Si single crystal substrate from the vicinity thereof, and an atmosphere having a higher partial pressure of the oxidizing gas than other parts is formed only in the vicinity of the single crystal substrate.
The method for manufacturing an SOI device according to any one of (12) to (12). (14) When the Si single crystal substrate has a substrate surface area of 10
cm ² or more, and rotating within the substrate to provide the oxidizing gas high partial pressure atmosphere over the entire single crystal substrate, thereby achieving substantially uniform oxidation over the entire substrate surface of the single crystal substrate. The method for manufacturing an SOI device according to any one of the above (8) to (13), wherein the SOI device forms an object thin film. (15) When forming the epitaxial film, the S
(8) to heating the i single crystal substrate to 750 ° C. or more
(14) The method for manufacturing an SOI device according to any of (14).

[0012]

The present invention relates to a Si single crystal substrate and a composition Zr _{1 -x} R _x O ₂ -δ formed on the Si single crystal substrate.
An SOI device such as a thin film transistor is constituted by a structure including an insulating layer which is an epitaxial film and an Si film formed on the insulating layer. Composition Zr _1-x R
_{The xO2 -} δ epitaxial film is stable at a high temperature, and is not reduced at a high temperature like sapphire and does not contaminate the Si film. In addition, the insulating property is high, and it is possible to completely insulate the Si film and the Si of the substrate. Further, the lattice constant is close to that of Si, and the crystallinity of the Si semiconductor thin film is improved. Furthermore, the surface of the epitaxial film having the composition Zr ₁ -xR _x O ₂ -δ is flat at the molecular level, and the continuity of the Si film formed thereon is increased. Furthermore, the effect of reducing the residual stress, which is considered to be based on the difference in the thermal expansion coefficient between the Si single crystal substrate and the epitaxial film having the composition Zr ₁ -xR _x O ₂ -δ was also confirmed. Although the details are unknown, this effect is remarkable particularly in the composition film where x is near 0, and it is presumed that the residual stress with Si is reduced due to the phase transition of ZrO ₂ .

As described above, the SOI device of the present invention is
Performance can be enhanced with devices for each application.

[0014]

DETAILED DESCRIPTION The SOI device of the present invention can be applied to, for example, a thin film transistor (TFT). One example of the basic structure is shown in FIG. The TFT includes a Si single crystal substrate 1, an insulating layer 2 formed thereon, a Si semiconductor thin film 3 formed on the insulating layer 2, source and drain electrodes 4, 5, and a gate insulating layer. 6 and a gate electrode 7 formed on the gate insulating layer 6.

In the SOI device of the present invention, the insulating layer is formed on the surface of a single-crystal Si substrate and has a composition substantially stabilized by zirconium oxide or a rare earth metal. In general, the composition has a composition of Zr _1-x R _x O _2- δ
(Where R is a rare earth metal containing Y, x = 0 to 0)
0.75, preferably 0.2 to 0.50).

The crystallinity of this oxide epitaxial film is x
And the range of Jan. J. Appl. Phys. 2
7 (8) L1404-L1405 (1988), in a small region where x is less than 0.2, Zr
_1-x R _x O _{2- δ} becomes tetragonal. Above that,
Become cubic. In the cubic region, a mono-oriented epitaxial film is obtained. Appln. Phys. 58 (6) 2407-
As described in 2409 (1985), the other orientation plane to be obtained is mixed, and a single orientation epitaxial film has not been obtained.

Therefore, it is preferable that the crystal of the insulating layer is cubic and has a single crystallinity.
In the SOI device of the present invention, epitaxial Si may be provided as a functional layer on the surface of the insulating layer. In this case, the crystals of the insulating layer are more regularly arranged in the cubic system than in the tetragonal system. This is because Si formed thereon is easily grown epitaxially. Further, in a thin film having a plurality of crystal planes, a grain boundary exists, and when a high electric field is applied to the thin film, local electric field concentration occurs at the grain boundary, and the thin film is easily deteriorated.

On the other hand, in the region where x exceeds 0.75, the crystal is cubic, but a plane other than the target crystal plane is mixed. For example, when an attempt is made to obtain a (100) epitaxial film of Zr _{1 -x} R _x O ₂ -δ, a crystal of (111) is mixed in this range.

That is, from the range where a cubic crystal can be formed and the range where a desired crystal plane can be obtained, _{x in} Zr _1-x R _x O _2- δ is 0 to 0.75, preferably 0.2 to 0.50. Within this range, an excellent epitaxial film can be obtained as an insulating layer film.

In particular, even when the insulating layer film is a high-purity epitaxial film of ZrO _{2 having} a composition of ZrO ₂ of 93 mol% or more in terms of only the constituent elements excluding oxygen, it is a single-oriented epitaxial film. Is preferred. Conventionally, Z
In the case of an epitaxial film having a high purity of ZrO ₂ with r of 93 mol% or more, a mono-oriented epitaxial film has not been obtained conventionally. However, the present inventors first converted it to only constituent elements excluding oxygen. As a result, a single oriented film of an epitaxial film having a high purity of ZrO ₂ with a Zr content of 93 mol% or more was obtained.

The epitaxial film referred to here is:
Assuming that the substrate surface of the film is the XY plane and the film thickness direction is the Z axis,
The crystal is oriented along the X-axis, Y-axis and Z-axis directions, and the intensity other than the intended reflection in X-ray or electron beam diffraction measured from each direction is the maximum intensity of the intended surface. Refers to those of 5% or less. For example, in the (001) epitaxial film, that is, the c-plane epitaxial film, the reflection intensity of the film other than the (00l (ell)) plane in 2θ-θ X-ray diffraction is 5 times of the maximum peak intensity of the (001 (ell)) plane reflection. % Or less and a film showing a spot or streak pattern in the RHEED evaluation can be said to be a (001) epitaxial film. The same applies to the (111) epitaxial film.

The term "single-oriented film" as used herein means a crystallized film in which the target crystal planes are aligned in parallel with the substrate surface. Indicates that the reflection intensity other than the (001) plane in the 2θ-θ X-ray diffraction of the film is 5% or less of the maximum peak intensity of the (001 (ell)) plane reflection. Similarly, in the (111) single orientation film, the reflection intensity other than the (l (ell) l (ell) l (ell)) plane is (l (ell) l (ell) l (ell)).
It refers to those having 5% or less of the maximum peak intensity of surface reflection.

It is preferable that the ZrO ₂ thin film has a Zr content of 93 mol% or more, particularly 95 mol% or more, further 98 mol% or more, and further 99.5 mol% or more in terms of constituent elements excluding oxygen. The higher the purity, the higher the insulation resistance and the smaller the leakage current.

The type of the rare earth metal is selected in order to preferably match the lattice constant of the functional film formed on the oxide thin film with the lattice constant of the oxide thin film.
For example, Zr _0.7 R _0.3 O using Y as a rare earth metal
The lattice constant of _2- δ was 0.515 nm. This value can be changed by the value of x. When a YBCO film (lattice constant: 0.386 nm), which is a functional film described later, is provided on this film, the lattice of the surface of the Zr _0.7 R _0.3 O _2- δ film is 45 °.
By rotating, the grid is matched and can be further adjusted by the value of x. However, there is a limit when the adjustable region of matching is within x. Therefore, matching can be made possible by changing the type of rare earth. For example, rare earth Pr is used instead of Y. At this time, the lattice constant of Zr _1-x R _x O _2- δ can be increased, and the matching with the Si crystal can be optimized. By selecting the kind and amount of the rare earth in this way, it is possible to preferably match the lattice of the functional film.

The upper limit of the Zr content is 99.99% at present. The insulating layer film has a P content of less than 7 mol%.
And the like.

The zirconium oxide containing no oxygen vacancies is represented by the chemical formula ZrO ₂ , but the amount of oxygen changes depending on the type, amount and valence of the added metal element in the zirconium oxide containing a rare earth containing Y. For this purpose, the composition of the oxide thin film of the present invention was expressed using the chemical formulas Zr _{1 -x} R _x O ₂ -δ and δ. δ is usually about 0 to 0.5.

The half-width of the rocking curve of reflection on the (002) plane or the (111) plane of the insulating layer film of the present invention is preferably 1.50 ° or less, and the surface of the insulating layer film has an 8% or less.
0% or more, preferably 90% or more, particularly 95% or more of A
The surface roughness by FM (ten-point average roughness R _z ) is the standard length 5
It is preferably 2 nm or less at 00 nm. Note that the above percentage is a value obtained by measuring at least 10 arbitrary locations distributed on average over the entire surface of the thin film. Further, the RHEED image of the insulating layer film also has a high streak property. That is, the RHEED image is streak and sharp. As described above, the oxide thin film of the present invention has good crystallinity and good surface properties. There is no particular lower limit for the half width of the rocking curve and the ten-point average roughness _Rz at a reference length of 500 nm, but the smaller the smaller, the better. At present, the lower limit is that the half width of the rocking curve is about 0.7 °, and the ten-point average roughness R _z at a reference length of 500 nm is about 0.10 nm.

In the SOI device of the present invention, the substrate surface of the Si single crystal substrate, that is, the thin film forming surface side is oxidized shallowly (for example, about 5 nm or less), and SiO ₂
Etc. may be formed. This is because oxygen in the ZrO ₂ thin film may diffuse to the substrate surface of the Si single crystal substrate. Also, depending on the method of film formation, ZrO
_{(2) When a} thin film is formed, a Si oxide layer may remain on the Si substrate surface.

The thickness of the Zr _1-x R _x O _2- δ thin film is 0.5
A film thickness of about 500 to 500 nm, preferably about 1 to 300 nm, and particularly 50 to 500 nm is selected for an SOI device that requires insulating properties.

When the above-described compositional Zr _{1 -x} R _x O ₂ -δ epitaxial film is used as the insulating layer film of the SOI device of the present invention, the disturbance of the physical quantity due to the grain boundaries is eliminated, and a good function is exhibited. .

The Si semiconductor film formed on the insulating layer described above is preferably composed of an Si film that is an epitaxial Si film, a polycrystalline Si film, or an amorphous Si film.

In an SOI device having a Si semiconductor film composed of an epitaxial Si film, since the substrate on which the Si film is formed is covered with an epitaxial film containing ZrO ₂ as a main component, impurities in the Si semiconductor film, for example, , Conventional S
Al, which is an impurity from sapphire in the OS structure, is reduced, and the semiconductor film characteristics (eg, mobility) of the Si film are improved. Further, by matching the thermal expansion coefficients of ZrO ₂ and Si, the stress in the Si film is reduced, and the crystallinity of the Si epitaxial film is improved. As described above, since a high-quality Si semiconductor film can be obtained on an insulating substrate, the present invention is more effective when applied to a bipolar CMOS device or the like, including the TFT of one example of the SOI device in FIG. In the case where an epitaxial film containing ZrO ₂ having high purity as a main component is used for the insulating layer, the insulating property is particularly improved, and an IC is formed on a bulk Si substrate.
By manufacturing the device, a three-dimensional device is also possible.

In an SOI device having a Si semiconductor film made of polycrystalline Si, the polycrystalline Si is oriented to Si (100) because the insulating layer film has high crystallinity.
Therefore, since there are few grain boundaries connected in the in-plane direction of the film, semiconductor characteristics (for example, leak current, switching characteristics, etc.) in the in-plane direction in the polycrystalline Si film are improved.

Then, S made of amorphous Si
In an SOI device including an i-semiconductor film, its semiconductor characteristics are greatly affected by the flatness of the interface between the amorphous Si film and the substrate and the surface, and the continuity of the film. The insulating layer film in the SOI device of the present invention is, as described above,
It has excellent flatness and has only irregularities on the molecular level. Therefore, the amorphous Si formed thereon is made of ZrO ₂
The interface with the insulating layer film mainly composed of is also flat, and the surface irregularities are extremely small. Further, the wettability between ZrO ₂ and Si is good, and the continuity is excellent even with a small film thickness. Therefore,
An excellent amorphous Si film can be obtained by the effect of ZrO _2. For example, when a TFT is formed, an element having excellent switching characteristics can be manufactured.

As described above, the Si film has a thickness of 5 to 2000 nm.
A film thickness of the order of magnitude is selected for each SOI device application.

TF which is one of the SOI devices of the present invention
For the T element, it is preferable to use an epitaxial or polycrystalline Si film of about 100 to 500 nm. In a TFT element using an amorphous Si film, 5 to 5
It is preferable to use a thin film of about 0 nm. Thinner T
Although it is possible to reduce the leakage current of the FT element,
Considering the film quality, a thickness of about several tens nm is particularly preferable.

The above-mentioned source electrode, drain electrode and gate electrode may be formed of ordinary materials used in SOI devices, and are preferably formed of, for example, Al or Si.

The gate insulating layer may be formed of a usual material used for an SOI device.
₂ , Si ₃ N ₄ , ZrO ₂ or the like.

Next, a method of manufacturing an SOI device according to the present invention will be described in detail focusing on the method of forming the insulating layer and the Si semiconductor film.

In carrying out the forming method of the present invention, it is desirable to use a vapor deposition apparatus 11 as shown in FIG.

The vapor deposition apparatus 11 has a vacuum chamber 11a, in which a holder 13 for holding a single crystal substrate 12 is arranged at a lower part. The holder 13 is connected to a motor 15 via a rotating shaft 14, and is rotated by the motor 15 so that the single crystal substrate 12 can be rotated in the substrate plane.
A heater 16 for heating the single crystal substrate 12 is built in the holder 13.

The vapor deposition device 11 further includes an oxidizing gas supply device 17, and an oxidizing gas supply port 18 of the oxidizing gas supply device 17 is disposed immediately below the holder 13. Thus, the partial pressure of the oxidizing gas is increased near the single crystal substrate 12.
Below the holder 13, a Zr evaporator 19 and a rare earth metal evaporator 20 are arranged. The Zr evaporator 19 and the rare earth metal evaporator 20 are provided with an energy supply device for supplying energy for evaporation to a metal source such as an electron beam generator, in addition to the respective metal sources. . In the drawings, P is a vacuum pump.

Hereinafter, a method for forming the insulating layer film will be described.

In this method, first, a single crystal substrate is set on the holder. At this time, a single crystal substrate of Si is used as the single crystal substrate, and the (100) plane or the (11) plane is used as the substrate surface on which the target insulating layer film is formed.
1) A face is selected. This is because the insulating layer film formed on the substrate surface is made into a single crystal epitaxially grown, and the crystal is oriented in an appropriate direction. Preferably, the substrate surface is etched and cleaned using a mirror-finished wafer. The etching cleaning is performed with a 40% ammonium fluoride aqueous solution or the like. At this time, the Si single crystal substrate can have a substrate area of, for example, 10 cm ² or more. As a result, the SOI device can be made extremely inexpensive as compared with the related art. Although there is no particular upper limit on the area of the substrate, it is about 400 cm ² at present. As a result, a semiconductor process using a 2-inch to 8-inch Si wafer, particularly a 6-inch type, is now mainstream and can cope with this.

Since the cleaned Si single crystal substrate has extremely high reactivity, it is necessary to protect the Zr _{1 -x} R _x
For the purpose of growing a good epitaxial film containing O ₂ -δ as a main component, the substrate surface of the Si single crystal substrate is subjected to a surface treatment as follows.

First, a Si single crystal substrate whose surface has been cleaned is placed in a vacuum chamber and heated while introducing an oxidizing gas to form a Si oxide layer on the surface of the Si single crystal substrate. Oxidizing gases include oxygen, ozone, atomic oxygen,
NO ₂ or the like can be used. Since the surface of the cleaned Si single crystal substrate is extremely reactive as described above, it is used as a protective film to protect the surface of the Si single crystal substrate from rearrangement and contamination. The thickness of the Si oxide layer is preferably about 0.2 to 10 nm.
If the thickness is less than 0.2 nm, the protection of the Si surface is incomplete. The reason for setting the upper limit to 10 nm will be described later.

The above-mentioned heating is carried out at a temperature of 300 to 700 ° C. for about 0 to 10 minutes. At this time, the heating rate is about 30 to 70 ° C./min. If the temperature is too high,
If the rate of temperature rise is too fast, the formation of the Si oxide film will be insufficient, and conversely, if the temperature is too low or the holding time is too long,
The Si oxide film is too thick.

When oxidizing gas is introduced, for example, when oxygen is used as oxidizing gas, the inside of the vacuum chamber is initially 1 × 10 ^-7 to 1
It is preferable that the vacuum is set to about × 10 ⁻⁴ Torr, and the introduction of an oxidizing gas is performed so that at least the oxygen partial pressure of the atmosphere near the Si single crystal substrate becomes 1 × 10 ⁻⁴ .
The state in which the oxygen partial pressure of this atmosphere has an upper limit is a pure oxygen state, but it may be air, particularly preferably about 1 × 10 ⁻¹ Torr or less.

After the above steps, heating is performed in a vacuum. Since the Si surface crystal is protected by the protective film, there is no contamination such as formation of a SiC film by reacting with hydrocarbons as residual gas.

The heating temperature is 600 to 1200 ° C., especially 7
The temperature is preferably set to 00 to 1100 ° C. If the temperature is lower than 600 ° C., a 1 × 1 structure described later cannot be obtained on the surface of the Si single crystal substrate. If the temperature exceeds 1200 ° C., Si
The protection of the surface crystal is not sufficient, and the crystallinity of the Si single crystal substrate is disturbed.

Next, Zr and an oxidizing gas or Zr, a rare earth (including Y) metal and an oxidizing gas are supplied to the surface. In this process, the metal such as Zr is replaced with the Si formed in the previous process.
The oxide protective film is reduced and removed. At the same time, a 1 × 1 surface structure is formed on the exposed Si surface crystal surface by Zr and oxygen or Zr, a rare earth metal (including Y) and oxygen.

The surface structure is determined by reflection high-energy electron diffraction (Refle
ction High Energy Electron Diffraction: Below, RH
(Referred to as EED). For example, in the case of a 1 × 1 surface structure aimed at by the present invention, the electron beam incident direction is [110], and a complete streak pattern with a one-time period C1 as shown in FIG. Is exactly the same pattern even if is set to [1-10]. On the other hand, the clean Si single crystal surface has a surface structure of, for example, 1 × 2, 2 × 1, or a mixture of 1 × 2 and 2 × 1 in the case of a (100) plane. In such a case, the pattern of the RHEED image has a one-time period as shown in FIG. 3B in either or both of the electron beam incident directions [110] and [1-10]. A pattern having C1 and a double cycle C2 is obtained. In the 1 × 1 surface structure of the present invention, when viewed from the RHEED pattern, the incident direction is both [110] and [1-10], and the double cycle C2 of FIG. 3B is not observed.

The clean surface of Si (100) is 1 × 1
The structure may be indicated. Although it has been observed several times in our experiments, it is impossible at present to obtain 1 × 1 on a Si-clean surface with an unclear, stable and reproducible condition showing 1 × 1.

S of any structure of 1 × 2, 2 × 1, and 1 × 1
The i-clean surface is easily contaminated at high temperatures in a vacuum, and reacts particularly with hydrocarbons contained in the residual gas to form SiC on the surface, and the crystal on the substrate surface is disturbed. Therefore, it has not been possible to stably form a 1 × 1 structure suitable for crystal growth of an oxide film on a Si substrate.

The Si (100) plane has been described above as an example, but the (111) plane has a similar structure although the structure of the clean surface is different, but an oxide film is grown on the Si substrate. Until now, it has been impossible to stably form a suitable 1 × 1 structure.

Zr or Zr and rare earth (including Y)
The supply amount of the metal is, in terms of its oxide, 0.3 to 10 nm,
Particularly, about 3 to 7 is preferable. If it is less than 0.3 nm, the effect of reducing the Si oxide cannot be sufficiently exerted, and if it exceeds 10 nm, irregularities at the atomic level are likely to be generated on the surface. This is because it may not be. The reason why the preferable upper limit of the thickness of the Si oxide layer is set to 10 nm is that if the thickness exceeds 10 nm, the Si oxide layer may not be sufficiently reduced even if the metal is supplied as described above. Because it comes out.

When oxygen is used as the oxidizing gas, 2
It is preferable to supply about 50 cc / min. The optimum amount of oxygen is determined by the size of the vacuum chamber, the pumping speed of the pump, and other factors, and the optimum flow rate is determined in advance.

The surface treatment of the Si substrate has the following effects.

The surface structure of the crystal surface in several atomic layers is as follows:
This is generally different from a virtual surface atomic arrangement structure that can be considered when a bulk (three-dimensional large crystal) crystal structure is cut. This is because the disappearance of the crystal on one side changes the situation around the atoms that have appeared on the surface, and correspondingly tries to become a stable state with lower energy. The structural change mainly includes a case where the atomic position is merely relaxed and a case where the rearrangement of atoms occurs to form a rearranged structure. The former is present on most crystal surfaces. The latter generally form a superlattice structure on the surface. When the magnitudes of the unit vectors of the bulk surface structure are a and b, a superlattice structure having a magnitude of ma and nb is called an m × n structure. The surface of the cleaned Si (100) has a 1 × 2 or 2 × 1 structure, and the Si (111) surface has a complex superstructure having a large unit mesh of a 7 × 7 or 2 × 8 structure. In addition, these purified S
The i-surface is highly reactive, and reacts particularly with a residual gas in a vacuum, especially a hydrocarbon, at a temperature (700 ° C. or higher) at which an oxide thin film is epitaxially formed, and the Si surface is formed on the surface.
The formation of C contaminates the substrate surface and disturbs surface crystals.

In order to epitaxially grow an oxide on a Si substrate, the structure of the Si surface must be stable and play a role of transmitting crystal structure information to the grown oxide film. In the oxide epitaxial film crystal,
Since the atomic arrangement structure considered when cutting the bulk crystal structure is a 1 × 1 structure, the surface structure of the substrate for epitaxially growing an oxide is 1 × 2, 2 × 1, 7
Complex superstructures with large unit meshes of × 7 or 2 × 8 structures are not preferred and require a stable 1 × 1 structure. In addition, since the epitaxial growth is performed at a temperature of 700 ° C. or more, it is necessary to protect the reactive Si surface.

Next, as described above, S
A single-oriented epitaxial film containing ZrO ₂ as a main component is formed using an i-single-crystal substrate.

In forming a single-oriented epitaxial film containing ZrO ₂ as a main component, first, a Si single crystal substrate whose surface has been treated is heated. The heating temperature at the time of film formation is desirably 400 ° C. or higher for crystallization of ZrO ₂ ,
Furthermore, the crystallinity is excellent at about 750 ° C. or more, and particularly preferably 850 ° C. or more in order to obtain the crystal surface flatness at the molecular level film. Note that the upper limit of the heating temperature of the single crystal substrate is 1300
It is about ° C.

Next, Zr is heated by an electron beam or the like to evaporate. Zr metal and an oxidizing gas are supplied to the single crystal substrate. If necessary, rare earth elements (including Y) are supplied in the same manner. A thin film containing ZrO ₂ as a main component is obtained. ZrO
_{(2) A} simple substance undergoes a phase transition from a cubic crystal to a tetragonal crystal to a monoclinic crystal at room temperature from a high temperature. Stabilized zirconia is obtained by adding a rare earth metal (including Y) to stabilize a cubic crystal. In order to use ZrO ₂ as a buffer layer for crystal growth of epitaxial Si or the like, it is preferable to use a cubic film having high symmetry. Therefore, each metal element of Zr and a rare earth metal (including Y) is simultaneously evaporated from separate evaporation sources while controlling the ratio of Zr / rare earth metal, and deposited on a single crystal substrate. Here, the rare earth metal (Y
) / Zr is preferably from 0 to 3.0, and more preferably from 0.25 to 1.0. This allows
An oxide thin film having the above preferred composition ratio can be obtained.
Here, the film formation rate is desirably 0.05 to 1.00 nm / s, preferably 0.100 to 0.500 nm / s. The reason is that if it is too slow, the substrate will be oxidized, and if it is too early, the formed thin film will have poor crystallinity and will have irregularities on the surface. Therefore, the optimum value of the film formation rate is determined by the amount of oxygen introduced. Therefore, prior to the deposition of the ZrO ₂ thin film, how much the Zr metal and the rare earth metal (including Y) evaporate per unit time depending on the amount of power applied to the deposition source, and deposit the deposited films of these metals and oxides. Whether it is formed or not is measured and calibrated by a film thickness meter installed near the substrate in the vacuum evaporation tank. As the oxidizing gas, oxygen, ozone, atomic oxygen, NO ₂ or the like can be used. Here, description will be made on the assumption that oxygen is used. Oxygen is continuously evacuated from the chamber by a vacuum pump while continuously injecting oxygen gas at 2 to 50 cc / min, preferably 5 to 25 cc / min, by a nozzle provided in the vacuum evaporation tank. An oxygen atmosphere of about 10 ^-3 to 10 ^-1 Torr is formed at least in the vicinity of the single crystal substrate. The optimal oxygen amount is determined by the size of the chamber, the pumping speed of the pump, and other factors, and an appropriate flow rate is determined in advance. Here, the upper limit of the oxygen gas pressure is set to 10 ^-1 Torr so that the metal source in the evaporation source in the vacuum chamber is not degraded and the evaporation rate is deposited at a constant rate. Further, when introducing oxygen gas into the vacuum deposition tank, it is preferable to inject oxygen gas from the vicinity of the surface of the single crystal substrate to create an atmosphere with a high oxygen partial pressure only in the vicinity of the single crystal substrate. The reaction on the substrate can be further promoted by the amount introduced. At this time, since the inside of the vacuum chamber is continuously evacuated, most of the vacuum chamber has a low pressure of 10 ^-4 to 10 ^-6 Torr.

[0064] In narrow region ² of about 1cm of the single-crystal substrate, it is possible to promote the oxidation reaction on the single crystal substrate in this manner, the substrate area of 10 cm ² or more, for example, a diameter of 2
Fig. 1
By rotating the substrate as described above and supplying a high oxygen partial pressure to the entire surface of the substrate, a large-area film can be formed. At this time, the rotation speed of the substrate is desirably 10 rpm or more. This is because if the number of rotations is low, a film thickness distribution occurs in the substrate surface. Although there is no particular upper limit on the number of rotations of the substrate, it is usually about 120 rpm due to the mechanism of the vacuum apparatus.

Although the details of the manufacturing method have been described above, this manufacturing method is particularly clear in comparison with the conventional vacuum vapor deposition method, sputtering method, and laser ablation method. Since it can be carried out under easy operation conditions, it is suitable for obtaining a target substance with high reproducibility and high completeness over a large area. In addition, the method
Even if a BE apparatus is used, a target thin film can be obtained in exactly the same manner.

Since the single-oriented epitaxial film obtained as described above is used as an insulating layer of an SOI device, thereafter, a Si semiconductor film as a functional film, source and drain electrodes are formed by using a normal semiconductor manufacturing technique. , A gate insulating film, a gate electrode and the like are formed to form an SOI device.

In the present invention, it is particularly preferable that the functional film is formed of an epitaxial Si film. This epitaxial Si film is formed by a vacuum deposition method, a sputtering method,
Although any of the laser ablation method, the CVD method, the MBE method, and the like can be used, the above-described method of forming the insulating layer film can be used almost as it is except for the introduction of the oxidizing gas.

In this case, the degree of vacuum in the vacuum chamber is set to 10 ^-9 Torr.
Under the following ultra-high vacuum, film formation can be performed using ordinary MBE growth conditions as they are. The pressure may be about 10 ⁻⁷ Torr, but in this case, the substrate temperature needs to be as high as about 1000 ° C., and the film formation rate needs to be as low as about 0.05 nm / sec.

[0069]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

In manufacturing the SOI device, a vapor deposition apparatus having the structure shown in FIG. 2 was used.

Example 1 As a single crystal substrate on which an insulating layer film is grown, a Si single crystal cut and mirror-polished so that the surface becomes (100) plane, and cut and mirror-polished so that the surface becomes (111) Polished single crystal Si was used. After the purchase, the mirror surface was cleaned by etching with a 40% ammonium fluoride aqueous solution. Note that all the single crystal substrates used were circular substrates having a diameter of 2 inches.

The single crystal substrate was fixed to a substrate holder provided with a rotation and heating mechanism installed in a vacuum chamber, and the vacuum evaporation chamber was evacuated to 10 ^-6 Torr by an oil diffusion pump. Heat and rotate. The rotation speed is
20 rpm.

Thereafter, metals Zr and Y were simultaneously supplied from independent evaporation sources while controlling the molar ratio of Y / Zr to 0.45. At this time, no oxygen is introduced. When the supply amount reaches 1 nm in terms of the film thickness of the Zr + Y alloy, oxygen gas is introduced from the nozzle at a rate of 10 cc / min, and the metal and oxygen are reacted to form an YSZ film of about 10 nm, which is an oxide thin film. Obtained.

FIG. 4 shows the results of XRD (CuKα ray) measurement of the oxide thin film obtained in this example. FIG.
FIG. 4A is an X-ray diffraction diagram when a substrate is used, and FIG. 4B is an X-ray diffraction diagram when a substrate is used. FIG. 4 (a) shows Y
The (002) peak of the fluorite structure of SZ is clearly observed, and the (111) peak of the fluorite structure is clearly observed in FIG. 4 (b), demonstrating the crystal structure and symmetry of the substrate. It can be seen that a crystal film strongly oriented in the reflected direction is obtained.

FIG. 5 shows an electron diffraction pattern showing the crystal structure of the thin film using the substrate. Here, FIG. 5A is a diffraction pattern when an electron beam is incident from the [100] direction of Si, and FIG. 5B is a diffraction pattern when an electron beam is incident from the [110] direction of the Si substrate. As can be seen from the results, the diffraction pattern of YSZ has a sharp streak shape, indicating that the film is a single crystal and the surface is flat at the atomic level. In addition, a sample of 5 × 5 mm square was cut out of the thin film using the above substrate on a straight line including the center of the thin film, and an AFM (Atomic Foam) was cut out.
rce Microscopy: Atomic force microscope). The surface image is shown in FIG. No grain boundaries are observed. this is,
The same was true when a substrate was used. It turns out that it is flat at the atomic level. Further, using the thin film surface images of all the samples, the ten-point average roughness R according to JIS B0610 was used.
_{When z} (reference length L: 500 nm) was measured, it was 0.17 nm on average and 0.12 m at minimum. The half width of the rocking curve is 1.0 ° on average and 0.9% at minimum.
°. From these, it was confirmed that the entire surface of the sample was a sample having excellent surface properties and crystallinity.

Example 2 In the same manner as described above, a single crystal substrate was cut so that its surface was a (100) plane, mirror-polished Si single crystal, and its surface was cut so that its surface was (111). A mirror-polished Si single crystal wafer was used. After the purchase, the mirror surface was cleaned by etching with a 40% ammonium fluoride aqueous solution. Note that a circular substrate having a diameter of 2 inches was used as the Si substrate.

The single crystal substrate was fixed to a substrate holder provided with a rotation and heating mechanism installed in a vacuum chamber, and the vacuum evaporation chamber was evacuated to 10 ⁻⁶ Torr by an oil diffusion pump. The substrate is rotated at 20 rpm to protect it with a substance, and oxygen is introduced near the substrate from the nozzle.
It was heated at 600 ° C. while introducing at a rate of 5 cc / min.
Here, a Si oxide film is formed on the surface of the substrate by thermal oxidation. By this method, a Si oxide film of about 1 nm was formed.

Then, the substrate was heated to 900 ° C. and rotated. The rotation speed was 20 rpm. At this time, oxygen gas was introduced from the nozzle at a rate of 25 cc / min, and a metal Zr was evaporated from the evaporation source on the substrate by:
By supplying 5 nm in terms of the thickness of the Zr metal oxide, a Si surface-treated substrate having a 1 × 1 surface structure was obtained. b. By evaporating metal Zr from the evaporation source on the substrate,
By supplying 5 nm in terms of the thickness of the r metal oxide, a Si surface-treated substrate having a 1 × 1 surface structure was obtained. c The metal Zr and Y are evaporated on the substrate while suppressing the molar ratio of Y / Zr to 0.22 to 5 nm in terms of oxide film thickness.
Then, a Si surface-treated substrate having a 1 × 1 surface structure was obtained. Figures 7 to 9 show these surfaces measured by RHEED.

All of these were measured in the incident direction [110], and the patterns were completely the same even when rotated by 90 °. That is, S having a stable 1 × 1 surface structure
It is confirmed that an i-surface treated substrate has been obtained.

Further, metal Zr is supplied from the evaporation source onto the Si surface-treated substrate in a state where the substrate temperature is 900 ° C., the rotation speed is 20 rpm, and oxygen gas is introduced from the nozzle at a rate of 25 cc / min. A 10 nm thick ZrO ₂ film
Obtained on the substrates a and b. By supplying Zr and Y from the evaporation source under the same conditions on the c-treated substrate, a YSZ (Zr _0.92 Y _0.18 O ₂ -δ) film having a thickness of 10 nm was obtained.

X measured on the three types of obtained thin films
The results of the line diffraction are shown in FIGS. In the figure, a (002) peak of ZrO ₂ (FIG. 10) and a YSZ (002) peak (FIG. 12) are observed. In FIG. 11, the (111) peak of ZrO ₂ completely overlaps the peak of the Si substrate. It can be seen that a crystal film strongly oriented in the direction reflecting the crystal structures and symmetry of ZrO ₂ and YSZ was obtained. In particular, these peaks are reflections from only one reflection surface, respectively. It can be seen that the ZrO ₂ film is a single-orientation highly crystalline film which is not seen in the conventional example. Further, the half widths of the rocking curves of the reflections are 0.8 ° (actual value) and 0.9 ° (actual value), respectively.
It was 0.8 ° (actual value including the Si substrate), and it was confirmed that the orientation was excellent.

FIGS. 13 to 15 show the RHE of this thin film.
ED (Reflection High Energy Electron Diffraction
) Shows the pattern. The incident direction of the electron beam is [1] on the Si substrate.
10] direction. As can be seen from the results, the diffraction pattern on the surface of the thin film having this structure is a completely streak pattern, which is completely different from the pattern in which the streak is partially close to a spot in the conventional example. This completely streak pattern is ZrO ₂
Is excellent in crystallinity and surface properties. In addition, as a result of measuring the resistivity of the ZrO ₂ film and the YSZ film, it was found that ZrO ₂ showed a resistance five times higher than that of YSZ and was excellent in insulating properties. In addition, when ten points of average roughness Rz (reference length L: 500 nm) according to JIS B0610 were measured at almost ten locations of the three types of films over almost the entire surface,

For a ZrO ₂ film on a Si (100) substrate, the average is 0.65 nm, the maximum is 0.90 nm, and the minimum is 0.10 n.
m, for a ZrO ₂ film on a Si (111) substrate, the average is 0.1 μm.
80 nm, a maximum of 0.90 nm, a minimum of 0.10 nm, and an average of 0.7 for a YSZ film on a Si (100) substrate.
It was flat at a molecular level of 0 nm, a maximum of 0.90 nm, and a minimum of 0.12 nm.

Note that Y of the YSZ film is Pr, Ce, Nd,
When Gd, Tb, Dy, Ho, Er, etc. were changed, the same results as above were obtained.

Next, Zr on the Si (100) substrate
On the O ₂ film (insulating layer film), a Si semiconductor film (hereinafter, sometimes referred to as a Si film) as a functional layer was formed.

In this example, three types of Si films were formed.
In order to obtain an epitaxial Si film for Sample No. 1, a 200 nm Si film was formed at a substrate temperature of 900 ° C. and a film formation rate of 0.05 nm / sec by MBE. Atmospheric pressure CVD to obtain polycrystalline Si for sample No. 2
A 200 nm polycrystalline Si film was formed at a substrate temperature of 700 ° C. using SiH ₄ (concentration: 1%) diluted with H ₂ by the method, and a hydroxylation treatment was performed by hydrogen plasma. For sample No. 3, in order to obtain amorphous Si, plasma CVD
Using H ₄ gas, a film was formed at a substrate temperature of 300 ° C. and a thickness of 10 nm.
The results of evaluating these Si films by RHEED are shown in FIGS.
18. In (a), a streak pattern is observed, and it can be seen that Si is epitaxially grown on ZrO ₂ . In (b), a spot pattern of Si is observed. The spots are ring-shaped, which indicates that they are polycrystalline films. In particular, it can be seen that this film has strong crystal orientation and excellent crystallinity since the ring is in a state close to the spot. (C) shows a halo pattern and an amorphous state.

Next, such three kinds of Si films are formed by TFT
Process into The structure of the TFT is shown in FIG. This structure is called a planar type in a TFT.
A source electrode and a drain electrode of Al were formed to a thickness of 50 nm on the Si film by sputtering, and were patterned by etching. In order to make ohmic contact between the Al electrode and the Si semiconductor film, a device was devised using n-type conductive Si. Further, the plasma CVD method
_Two films were formed to a thickness of 200 nm to form gate insulating films. After patterning the gate insulating film, Al was deposited to a thickness of 50 nm. The gate electrode was prepared by etching the Al film, and sample Nos.
3 was obtained.

Sample N using epitaxial Si film
o. The TFT element 1 showed good transistor characteristics, and the electron mobility of 200 nm epitaxial Si using sapphire as a substrate was 200 cm ² / Vs, whereas the TFT element of this example was 400 cm ² / Vs. A double mobility was obtained. When using p-type conductive Si, the hole mobility was also 100 cm ² / Vs when using a sapphire substrate,
In the present invention, it was 200 cm ² / Vs. This is because the substrate of the Si film in the present embodiment is formed of ZrO ₂ , so that impurities (for example, Al when a sapphire substrate is used) are small, and the stress in the Si film due to ZrO ₂ and Si thermal expansion matching. It is considered that the crystallinity of the Si epitaxial film is improved due to the effect of the reduction in the thickness. Further, in this embodiment, the FET is made of a thin film. However, since such a high-quality Si film can be obtained on an insulating substrate, the effect can be further utilized when applied to a bipolar CMOS device. The ZrO ₂ layer has excellent insulating properties, and a three-dimensional device can be realized by manufacturing an IC on a bulk Si substrate.

Sample No. 2 using a polycrystalline Si film
In the ET element, a large difference was found in the leak current, in particular, as compared with a conventional polycrystalline Si TFT using a quartz substrate as a substrate. When 5 V was applied between the drain and the source and the gate voltage was compared at 0 V, the TFT manufactured using quartz in exactly the same manner as the present embodiment was 8.2 × 10
^-12 A / μm, whereas in the present invention 9.5 × 1
The leakage current was small by almost one digit of ^0-13 . It is considered that the polycrystalline Si of the present embodiment is oriented to Si (100) and thus has few grain boundaries connected in the in-plane direction of the film, so that a leak current path is hardly formed between the source and the drain.

Sample No. 3 using amorphous Si
The TFT device was compared with a conventional FET formed on glass. An FET on glass was also manufactured in exactly the same steps and conditions as in this example. Here, the amorphous Si film is
The thickness was set to be smaller (10 nm) than the thickness used for a normal TFT. This has the effect of reducing leakage due to the photoconductivity of the TFT. In comparison of TFTs made of amorphous Si, a large difference was found in the ratio of ON current / OFF current.
In order to use a TFT as a switching element, a high ON / OFF ratio is required. 5 for TFT on glass
In contrast to less than an order of magnitude, the present invention was able to take a ratio of 6 digits. The amorphous Si film used this time is 10
nm and thin. Therefore, the unevenness of the interface and the surface and the continuity of the film greatly affect the TFT characteristics. ZrO _{2 of the} present invention
As described above, the film is excellent in flatness and has only asperities at the molecular level.
Has a flat interface with ZrO ₂ and has no surface irregularities.
In addition, ZrO ₂ and Si have good wettability and excellent continuity even at a small film thickness. Therefore, Si which is more excellent due to the effect of ZrO ₂
A film is obtained, and TFT characteristics are also excellent.

Further, three types of Si semiconductor films were prepared on the other four types of substrates in Examples 1 and 2 in the same manner as above, and TFT samples were prepared.
00) An effect almost equivalent to that of a TFT obtained by forming a Si semiconductor film as a functional layer on a ZrO ₂ film (insulating layer film) on a substrate was obtained.

[0092]

As described above, the Sr using the epitaxially grown Zr _{1 -X} R _X O ₂ -δ thin film according to the present invention.
In the OI device, the insulating layer film made of Zr _{1 -X} R _X O ₂ -δ has high crystallinity and surface property, and has lattice matching with Si, thermal expansion coefficient matching with Si, and wettability with Si. Therefore, the semiconductor characteristics of the Si film formed on the insulating layer film are improved. Therefore, the transistor characteristics of the SOI device can be improved. More specifically, when an epitaxial Si film is used, the mobility of a semiconductor can be increased, so that not only excellent FET characteristics can be obtained, but also a bipolar CMOS, 3 A three-dimensional device can be easily realized. Furthermore, when a polycrystalline Si film is used, an SOI device with less leakage can be obtained, and when amorphous Si is used, an SOI device with excellent switching characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a basic structure of a TFT as an example of an SOI device according to the present invention.

FIG. 2 is a diagram illustrating an example of a vapor deposition apparatus used in the method for manufacturing an SOI device according to the present invention.

3A is a schematic diagram showing a RHEED pattern having a 1 × 1 surface structure, and FIG. 3B is a schematic diagram showing a 2 × 1, 1 × 2,
Alternatively, RHE of the surface structure when these are mixed
It is a schematic diagram which shows an ED pattern.

FIG. 4 is an X-ray diffraction diagram of a YSZ thin film obtained on a single crystal substrate, wherein (a) and (b) are each a single crystal Si substrate (using (100) plane) single crystal substrate. And a Si single crystal (using (111) plane) single crystal substrate.

FIG. 5 is a drawing-substitute photograph showing the crystal structure of a thin film,
FIG. 4A shows a reflection high-speed electron diffraction pattern of the YSZ film shown in FIG. 4A, where FIG. 4A shows the case where an electron beam is incident from the [100] direction of the Si single crystal substrate, and FIG.
It is a diffraction pattern when an electron beam enters from the [110] direction of the i single crystal substrate.

FIG. 6 is a drawing substitute photograph showing a crystal structure of a thin film,
5 is a thin-film surface image of the YSZ film shown in FIG. 4A by an atomic force microscope.

FIG. 7 is a drawing substitute photograph showing the surface structure of the Si substrate a in Example 2 having a 1 × 1 surface structure formed by Zr metal and oxygen, showing a RHEED pattern, It is a diffraction pattern in which an electron beam was incident from the crystal [110] direction.

FIG. 8 is a drawing substitute photograph showing the surface structure of the Si substrate b in Example 2 having a 1 × 1 surface structure formed by Zr metal and oxygen, showing a RHEED pattern, It is a diffraction pattern in which an electron beam was incident from the crystal [110] direction.

FIG. 9 shows 1 formed by Zr metal, Y metal and oxygen.
14 is a drawing substitute photograph showing the surface structure of the Si substrate c in Example 2 having a × 1 surface structure, which shows a RHEED pattern and is a diffraction pattern in which an electron beam is incident from the Si single crystal [110] direction. It is.

FIG. 10 is an X-ray diffraction diagram of a film structure of ZrO ₂ obtained on a Si (100) substrate.

FIG. 11 is an X-ray diffraction diagram of a film structure of ZrO ₂ obtained on a Si (111) substrate.

FIG. 12 is an X-ray diffraction diagram of a YSZ film structure obtained on a Si (100) substrate.

FIG. 13 is a drawing substitute photograph showing the crystal structure of ZrO ₂ obtained on a Si (100) substrate, showing a RHEED diffraction pattern when an electron beam is incident from [110] on a Si single crystal substrate. It is.

FIG. 14 is a drawing substitute photograph showing the crystal structure of ZrO ₂ obtained on a Si (111) substrate, showing a RHEED diffraction pattern when an electron beam is incident from [110] on a Si single crystal substrate. It is.

FIG. 15 is a drawing substitute photograph showing the crystal structure of YSZ obtained on a Si (100) substrate, showing a RHEED diffraction pattern when an electron beam is incident from [110] on a Si single crystal substrate. is there.

FIG. 16 shows a sample No. formed on a ZrO ₂ insulating layer.
1 is a drawing substitute photograph showing the surface structure of an epitaxial Si film for No. 1 and showing a RHEED pattern;
It is a figure which shows the diffraction pattern at the time of making an electron beam inject from [110] of a Si single crystal substrate.

FIG. 17 shows a sample No. formed on a ZrO ₂ insulating layer.
FIG. 4 is a drawing substitute photograph showing the surface structure of a polycrystalline Si film for No. 2 and showing a RHEED pattern and showing a diffraction pattern when an electron beam is incident from [110] on a Si single crystal substrate. .

FIG. 18 shows a sample No. formed on a ZrO ₂ insulating layer.
3 is a drawing-substitute photograph showing the surface structure of an amorphous Si film for No. 3 and showing a RHEED pattern;
It is a figure which shows the diffraction pattern at the time of making an electron beam inject from [110] of an i single crystal substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single crystal silicon substrate 2 Insulating layer 3 Si semiconductor film 4 Source electrode 5 Drain electrode 6 Gate insulating film 7 Gate electrode 11 Vapor deposition device 11a Vacuum tank 12 Single crystal substrate 13 Holder 14 Rotation axis 15 Motor 16 Heater 17 Oxidizing gas supply device 18 Oxidizing gas supply port 19 Zr evaporator 20 Rare earth metal evaporator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-160757 (JP, A) JP-A-6-9297 (JP, A) JP-A-5-267473 (JP, A) JP-A-5-267473 109629 (JP, A) JP-A-59-169121 (JP, A) U.S. Pat. No. 4,826,787 (US, A) Hirofumi FUKUMOTO, et. al. , "Hetero epitaxial Growth of Ytria-Stabilized Zirconia (YSZ) on Silicon", Jpn. J. Appl. Phys. VOL. 27, NO. 8, pp. L1404-L1405 Golekki, et. a l. , "Heteroepitaxial Si films on yttria-stabilized cubi czirconia substrates es", Appl. Phys. Let t. , March 1983, Vol. 42, No. 6, p. 501-503 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 27/12 H01L 21/02 H01L 21/203 H01L 21/205 H01L 21/31 H01L 21/312-21/318 H01L 29 / 786

Claims (15)

(57) [Claims] 1. An Si single-crystal substrate, an epitaxial film of zirconium oxide stabilized with zirconium oxide or a rare earth metal (including Y) formed as an insulating layer on the Si single-crystal substrate, and Wherein the composition of the zirconium oxide or the zirconium oxide stabilized with the rare earth metal contains 93 mol% or more of Zr in terms of only the constituent element excluding oxygen. ) Face or (111)
An SOI device in which a half width of a rocking curve of surface reflection is 1.5 ° or less, and at least 80% of a surface of the epitaxial film has a ten-point average roughness _Rz at a reference length of 500 nm of 2 nm or less. 2. The SOI device according to claim 1, wherein the SOI device has a thin film transistor structure in which a gate electrode is formed on the Si film via a gate insulating film. 3. The SOI device according to claim 1, wherein said Si film is made of epitaxial Si. 4. The SOI device according to claim 1, wherein said Si film is made of polycrystalline Si. 5. The SOI device according to claim 1, wherein said Si film is made of amorphous Si. 6. The Si single crystal substrate, wherein the substrate surface is formed of Zr metal or Zr metal and at least one rare earth metal (including Y) and oxygen.
The SOI device according to any one of claims 1 to 5, wherein a Si surface-treated substrate having a surface structure of × 1 is used. 7. The SOI device according to claim 1, wherein an Si single crystal is used as the Si single crystal substrate so that the (100) plane or the (111) plane is the substrate surface. 8. The method for manufacturing an SOI device according to claim 1, comprising a Si single crystal substrate, an insulating layer formed on the Si single crystal substrate, and a Si film formed on the insulating layer. A single crystal by heating the Si single crystal substrate, introducing an oxidizing gas into the vacuum layer, and evaporating an evaporation source consisting only of Zr or a metal or alloy of Zr and at least one rare earth metal (including Y). The oxide thin film is epitaxially grown on the substrate surface of the single crystal substrate by supplying to the substrate surface, and the composition is Zr _1-x R _x O _2- δ (where R is a rare earth metal containing Y, x = 0 to 0.75
It is. Δ is 0 to 0.5. ) Is formed as a single-layer epitaxial film, and this is used as the insulating layer.
Method for manufacturing I device. 9. A Si surface having a 1 × 1 surface structure formed by Zr or Zr and at least one rare earth metal (including Y) and oxygen as the Si single crystal substrate. 9. The method according to claim 8, wherein a processing substrate is used.
A method for manufacturing an OI device. 10. An Si oxide layer having a thickness of 0.2 to 10 nm is formed on the surface of the Si surface-treated substrate,
Thereafter, the substrate temperature is set to 600 to 1200 ° C., and an oxidizing gas is introduced into the vacuum chamber to at least set the atmosphere near the substrate to 1 × 10 ^-4 to 1 × 10 ^-1 Torr.
In this state, Zr or Zr and at least one rare earth metal (Y) are formed on the surface of the substrate on which the Si oxide layer is formed.
10. The method for manufacturing an SOI device according to claim 8, wherein a pretreated Si single crystal substrate is supplied by evaporation. 11. When forming the Si oxide, the Si single crystal substrate is placed in a vacuum chamber into which an oxidizing gas has been introduced.
11. The method for manufacturing an SOI device according to claim 10, wherein the Si oxide layer is formed by heating to 700 ° C. and setting the oxygen partial pressure of the atmosphere in the vacuum chamber at least near the substrate to 1 × 10 ⁻⁴ Torr or more. 12. The SOI according to claim 8, wherein an Si single crystal is used as the Si single crystal substrate such that the (100) plane or the (111) plane is the substrate surface.
Device manufacturing method. 13. An oxidizing gas is injected from the vicinity of the surface of the Si single crystal substrate from the vicinity thereof, and an atmosphere having a higher partial pressure of the oxidizing gas than other portions is formed only in the vicinity of the single crystal substrate. The manufacturing method of any one of the SOI devices. 14. The Si single crystal substrate having a substrate surface area of 10 cm ² or more and rotating in the substrate to provide the oxidizing gas high partial pressure atmosphere over the entire single crystal substrate. 14. The method for manufacturing an SOI device according to claim 8, wherein a substantially uniform oxide thin film is formed over the entire surface of the single crystal substrate. 15. When forming the epitaxial film,
9. The heating of the Si single crystal substrate to 750 ° C. or higher.
15. The method for manufacturing an SOI device according to any one of items 14 to 14.