JPH05299346A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable the crystalline oriented surface of a single crystal silicon film to be easily selected even if the single crystal silicon film is to be formed on an insulating substrate by zone melting down recrystallizing (ZMR) method. CONSTITUTION:The semiconductor device is composed of a substrate l, a first silicon concentration modulated layer 2, a silicon layer 3 to be single crystallized by ZMR method, second silicon modulated layer 4 and a surface protective layer 5. In such a constitution, the first silicon concentration modulated layer 2 is provided so as to control the crystalline orientation of the single crystal silicon layer 3 to be formed on the layer 2 by ZMR method while in order to form the single crystal layer 3 having the crystalline oriented surface of e.g. (100) or (111), the layer 3 is to be formed corresponding to respective cases so that the mutual action of the Si atoms in the interface between the concentration modulated layer 2 and the single crystalline silicon layer 3 may be made stronger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device used for an image input / output device such as a display and a sensor, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a semiconductor device such as a thin film transistor, various semiconductor devices in which a single crystal silicon thin film is formed on an insulating substrate and a manufacturing method thereof have been proposed. Most of the semiconductor devices of this type form an amorphous or polycrystalline silicon thin film on an insulating substrate, and once the amorphous or polycrystalline silicon thin film is melted by various heat sources, it is cooled, solidified, and recrystallized. And single crystallizing. In this case, the heat source includes laser light, electron beam, various lamp lights, wire-shaped carbon heater and the like.

By the way, the crystal orientation plane of the single crystal silicon obtained by such a conventional melt recrystallization method (the crystal plane of silicon appearing on the substrate surface) is the same when a seed crystal is used during the melt recrystallization. It is determined by the orientation plane of the seed crystal. At this time, when the insulating substrate has a structure in which a silicon oxide film or an insulating film is formed by various film forming methods on a silicon wafer, the substrate is amorphous or multi-layered on the substrate. Prior to forming crystalline silicon, a hole is made in the insulating film layer on the wafer, amorphous or polycrystalline silicon is formed so as to cover the hole, and the above-mentioned melt recrystallization is performed from the top of this hole. As a result, a part of the wafer can be used as a seed crystal.

On the other hand, when the insulating substrate is a so-called amorphous substrate such as quartz glass, the orientation plane of the recrystallized film cannot be controlled by the above method. Therefore, when the insulating substrate is an amorphous substrate, it is necessary to perform single crystallization by a method other than the above-mentioned method.
Zone Melting Recrystallizatio
n, that is, the ZMR method) is known. FIG.
(A), (b) is a figure for demonstrating the outline of a ZMR method. According to the ZMR method, a polycrystalline silicon film 202 is formed on a quartz glass substrate 201, and this polycrystalline silicon film 202 is formed.
After forming a silicon oxide film (not shown) as a surface protective layer on the polycrystalline silicon film 202 sandwiched between the quartz glass substrate 201 and the silicon oxide film in a band shape (as indicated by a region 8), a heating solvent is formed. Then, the melted region 8 in a strip shape is moved in one direction to sequentially solidify and recrystallize silicon along the direction to obtain a single crystal silicon film. At this time, as shown in FIG. 14, there is a region in a supercooled state in which the liquid state is maintained even after the melting point of silicon exceeds 1412 ° C. at the solid-liquid interface of the solidification of the molten silicon. It is said that the solid-liquid interface is formed by a collection of facets (small crystal planes) of the (111) plane, which is the slowest growing crystal plane of silicon in this supercooled region. The formation of single crystal silicon is caused by the movement of the band-shaped melting region 8 and the movement of the supercooled region, and the facet plane composed of the (111) plane of silicon is continuously grown in this supercooled region. It is done. As a method of forming the band-shaped melting region, there is a method of heating with a linear carbon heater placed in proximity to the substrate, an RF induction heating method, or the like. The moving speed of the band-shaped melting region in this ZMR method is about several mm / sec, and the characteristic of the ZMR method is that a state close to thermal equilibrium is realized at the solid-liquid interface of recrystallization. Further, in the ZMR method, the insulating substrate is quartz glass (or SiO ₂ layer), and the surface protective film during recrystallization is subjected to thermal CV.
When the SiO ₂ formed in D is used, a recrystallized film having a crystal orientation plane of (100) plane, that is, a single crystal silicon thin crystal orientation plane, is obtained even though a seed crystal is not used. Be done.

[0005]

As described above, conventionally, when a seed crystal is used, the crystal orientation plane of single crystal silicon formed on an insulating substrate is determined by the crystal plane of the seed crystal. Will end up. Further, when the ZMR method is used, the crystal orientation plane of single crystal silicon is set to the (100) plane. The reason why the crystal orientation plane is obtained as the (100) plane in the ZMR method has not been clarified at all. For this reason, a single crystal having another crystal orientation plane, for example, the (111) plane, is obtained by the ZMR method. The guidelines for obtaining a silicon film have not been established. Therefore, when the insulating substrate is an amorphous substrate, the ZMR method is effective,
At the present time, there is a drawback that single crystal silicon having a crystal orientation plane other than the (100) plane cannot be stably obtained by the ZMR method.

That is, in general, when a semiconductor device such as a thin film transistor is manufactured based on the semiconductor device, the characteristics of the semiconductor device are determined by the crystal orientation plane of the single crystal silicon of the semiconductor device used for manufacturing this semiconductor device. Therefore, it is desirable to be able to select the crystal orientation plane of single crystal silicon according to the type, characteristics, etc. of the semiconductor device to be manufactured, but at the present time, when trying to form a semiconductor device using the ZMR method, single crystal silicon There is a problem that it is difficult to properly select the crystal orientation plane of the above according to the semiconductor device.

According to the present invention, even when a single crystal silicon thin film is formed on an insulating substrate by the zone melting recrystallization method (ZMR method), the crystal orientation plane of the single crystal silicon thin film can be easily selected. Further, it is another object of the present invention to provide a semiconductor device having a structure that can obtain silicon films having different orientations in the same substrate and has a structure suitable for manufacturing various semiconductor devices, and a manufacturing method thereof.

[0008]

Means for Solving the Problems
The present invention has been completed by studying the crystal orientation plane of the recrystallized film by the MR method from a viewpoint different from the conventional one. That is, the inventor of the present application, when completing the present invention,
In the process of forming single crystal silicon by the ZMR method, the interaction at the interface between the substrate and the molten silicon, especially the interaction between silicon atoms in the substrate and the molten silicon, was also considered important.

Unlike single crystal silicon, quartz glass often used as an insulating substrate has a so-called amorphous structure having no regular arrangement of silicon atoms and oxygen atoms. However, even in such an amorphous structure, it is known that the arrangement of the atoms has regularity only when the atoms are very close to each other. Thus, the characteristics of the amorphous structure can be expressed. Specifically, the characteristics of the amorphous structure can be expressed by using a radial distribution function (hereinafter, referred to as RDF) in which the existence probability of surrounding atoms is expressed as a function of distance with a certain atom as the origin. The radial distribution function is obtained by X-ray diffraction, neutron beam diffraction, electron beam diffraction or the like.

FIG. 1A is a diagram showing a radial distribution function of amorphous SiO _2, that is, quartz glass. according to this,
Quartz glass is near the distance of 3Å (accurately 3.10Å)
It is said that Si-Si interaction is recognized in and the coordination number (the number of Si atoms surrounding the origin Si atom with a distance of 3.10Å) is "4". That is, amorphous S
In iO ₂ , four Si atoms are present around any Si atom with a distance of 3Å. FIG. 1 (b) is a two-dimensional view of this state in consideration of SiO ₂ bonds. In the figure, black circles represent Si atoms and white circles represent O atoms. Referring to FIG. 1 (b),
Three Si atoms (black circles) are present on the circumference of a circle (shown by a broken line) with a radius of 3Å centered on the Si atom (black circle). That is, when the silicon on the quartz glass substrate is zone-melted by the ZMR method, on the substrate surface at the interface between the quartz glass substrate and the molten silicon, about three silicon atoms are arranged on a circle with a radius of about 3Å. It is considered that Si atoms are present.

On the other hand, the relative positional relationship of Si atoms in single crystal silicon is as shown in FIGS. 2 (a) and 2 (b) when the crystal orientation plane is the (100) plane.
In the case of the 11) plane, it becomes as shown in FIGS. 3 (a) and 3 (b). 2 (b) and 3 (b), a circle (shown by a broken line) with a radius of 3Å centered on the Si atom is drawn.
As can be seen from FIGS. 2A and 2B, when the crystal orientation plane of the single crystal silicon is the (100) plane, there are four Si atoms near the circumference having a radius of 3Å, and FIG. (A),
As can be seen from (b), when the crystal orientation plane of single crystal silicon is the (111) plane, there are 6 Si atoms near the circumference having a radius of 3Å.

In the process of forming single crystal silicon by the ZMR method, considering that Si atoms mutually interact strongly at the interface between the substrate and the silicon crystal on the substrate, the side of the silicon crystal plane is centered on the Si atom. If there are four,
That is, it is advantageous in terms of interfacial energy when the orientation plane is the (100) plane. This is in agreement with the conventionally known result, that is, the orientation of the (100) plane can be obtained by single crystallizing silicon on SiO ₂ by the ZMR method.

Considering the case of (111) plane orientation based on such a model, in the (111) plane of single crystal silicon, as shown in FIGS. There are 6 Si atoms. In this state, if the existing state of silicon on the substrate side is changed so that the interaction at the interface between the substrate and the (111) -oriented single crystal silicon becomes low in energy, the (111) -oriented single crystal is changed. The inventor of the present application has conceived that silicon can be stably obtained also by the ZMR method. The present invention has been made based on the above technical idea.

FIG. 4 is a diagram showing a structural example of the semiconductor device of the present invention which is to be subjected to a single crystallization process by the ZMR method.
Referring to FIG. 4, the semiconductor device includes a substrate 1 and a first
Silicon concentration modulation layer 2, a silicon layer 3 to be single-crystallized by the ZMR method, and a second silicon concentration modulation layer 4
And a surface protective layer 5. Here, as the substrate 1, a substrate whose surface layer is made of an insulating material, for example, silicon oxide is used. Specifically, quartz glass can be used for the substrate 1 as a simple substance. Alternatively, a silicon oxide film formed on a metal, semiconductor, ceramic or the like by an appropriate method can be used. For example, a silicon wafer on which SiO ₂ is formed by thermal oxidation, or Fe, C
Metallic materials such as u and Al, ceramic materials such as alumina or zirconia, and various physical and vapor deposition methods, CVD methods,
The surface layer of the substrate 1 can be formed of a material such as SiO ₂ formed by a chemical film forming method. When quartz glass alone is used as the substrate 1, its thickness is selected from the requirements of mechanical strength of the substrate. Usually 0.3 mm ~
It is 5.0 mm, preferably 0.5 mm to 2.0 mm. For materials other than quartz glass, SiO ₂ is used as an insulating layer.
When a layer is formed and used as an insulating substrate, the S
The film thickness of the iO ₂ layer is set in consideration of the step of forming the first silicon concentration modulation layer 2. Usually, it is selected within the range of about 1 μm to 10 μm.

The first silicon concentration modulation layer 2 is provided to control the crystal orientation of the single crystal silicon layer formed by the ZMR method on the first silicon concentration modulation layer 2, and the single crystal silicon layer has its crystal orientation. When it is attempted to form the plane to be, for example, the (100) plane or the (111) plane, the interaction of Si atoms at the interface between the concentration modulation layer 2 and the single crystal silicon layer may be different depending on the case. It is formed to be large. More specifically, (10
The concentration of Si atoms on the (0) plane is 6.78 × 10 ¹⁸ /
cm ² and the concentration of Si atoms on the (111) plane is 7.83 × 10 ¹⁸ atoms / cm ² , the first silicon concentration modulation layer 2 is a single crystal silicon layer having a (100) orientation. 6.78 × 10 ¹⁸ pieces / cm ² when forming with
The silicon concentration is set as a guideline, and when single crystal silicon is to be formed in the (100) orientation, a silicon concentration of 7.83 × 10 ¹⁸ pieces / cm ² is formed as a guideline. To be done. However, it is not necessary for the entire first silicon concentration modulation layer 2 to have the above silicon concentration value, and it is sufficient that the necessary amount of Si atoms exists only at the interface in contact with the silicon layer 3.

Therefore, there is no special regulation on the amount of Si atoms inside the surface other than the surface in contact with the silicon layer 3, but in order to relax the strain generated by providing the first silicon concentration modulation layer 2, 1 silicon concentration modulation layer 2
It is desirable that the amount of Si atoms contained therein gradually decreases toward the substrate 1 side.

Various methods can be considered for forming the first silicon concentration modulation layer 2 on the surface of the insulating substrate 1 such as quartz glass (or SiO ₂ layer). For example, the first silicon concentration modulation layer 2 can be formed on the surface of the substrate 1 by a so-called ion implantation method in which silicon ions are accelerated in a vacuum at high speed by the effect of an electric field and collide with the substrate 1. This method is based on ion current density and implantation time.
There is an advantage that the injection amount of silicon into the first silicon concentration modulation layer 2 can be controlled with high accuracy. Alternatively, the first silicon concentration modulation layer 2 is formed on the surface of the substrate 1 by forming a material containing Si atoms on the surface of the substrate 1 and then performing a heat treatment to thermally diffuse the Si atoms into the substrate 1. can do. In addition, the first silicon concentration modulation layer 2
As described above, the crystal orientation of the single crystal silicon formed by the ZMR method on the (100) plane, or (1
11) Since it is provided for controlling the surface,
When the same crystal orientation is required over the entire area of the substrate 1, the silicon is formed so as to have a uniform silicon concentration over the entire area of the substrate 1. In the case where the orientation is different depending on the location such that one portion has (100) plane orientation and the other portion has (111) plane orientation on one substrate, the first
The silicon concentration modulation layer 2 is also formed with a different silicon concentration value for each place on the substrate depending on its orientation.

The silicon layer 3 which is to be single-crystallized by the ZMR method is made of polycrystalline silicon or amorphous silicon. This silicon layer 3 is generally formed by plasma CVD method, thermal CVD method, photo CVD method,
It is formed by using various film forming methods such as LPCVD method, MOCVD method, sputtering method, vacuum evaporation method, ion beam cluster film forming method, etc., but it is judged to be necessary in the process of zone melting recrystallization by ZMR method. In some cases, it may be processed into an arbitrary shape by using a normal photolithography technique. Specifically, it is processed into a shape such as a stripe shape, an island shape, or a continuous island shape as shown in FIGS. 5, 6, and 7, and by processing such a shape, the substrate 1 is processed. It is possible to limit the movement of the silicon melt and improve the stability of single crystal growth.

The second silicon concentration modulation layer 4, like the first silicon concentration modulation layer 2, is provided to control the crystal orientation of the single crystal silicon layer formed under the second silicon concentration modulation layer 4. The crystalline silicon layer has a crystal orientation plane of (1
When it is attempted to form the (00) plane or the (111) plane, the interaction of Si atoms is increased at the interface between the concentration modulation layer 4 and the single crystal silicon layer depending on the case. Is formed in.

As a method of forming the second silicon concentration modulation layer 4, a SiO ₂ thin film is formed on the silicon layer 3 and then silicon ions are converted into SiO ₂ by an ion implantation method.
There is a method of implanting the thin film and modulating the concentration of silicon ions in the silicon thin film to a desired value, or modulating the concentration of silicon by a thermal diffusion method.

The surface protective layer 5 is provided to prevent evaporation of the molten silicon in the ZMR method or to prevent the melt from moving inside the silicon layer processed as described above, and has a melting point higher than that of silicon. It is made of high material. Suitable materials include SiO ₂ , SiO,
There are Si ₃ N ₄ and SiN, and these can be deposited alone or in combination in plural on the second silicon concentration modulation layer 4 to form the surface protective layer 5. The surface protection layer 5 may be formed by plasma CVD method, thermal CVD method, or the like.
Method, optical CVD method, LPCVD method, MOCVD method, sputtering method, vacuum deposition method, various film forming methods such as ion beam cluster film forming method, and the like. The thin film is formed by being optimized within a range of about 0.5 μm to 5.0 μm, preferably 1.0 μm to 2.0 μm.

The silicon layer 3 of the semiconductor device shown in FIG. 4 having the above-mentioned structure is zone-melted by the known ZMR method,
By recrystallizing and changing to a single crystal silicon layer,
The semiconductor device according to the present invention can be obtained. In this ZMR method, as a method for forming a band-shaped heating / melting region, heating with a linear carbon heater placed close to the substrate, high-frequency heating using a carbon susceptor,
Halogen lamp heating, laser heating, electron beam heating, etc. are used.

FIG. 8 is a diagram showing a structural example of the semiconductor device of the present invention as a result of zone melting and recrystallization of the silicon layer 3 of the semiconductor device shown in FIG. 4 by the ZMR method. Referring to FIG. 8, the silicon layer 3 of the semiconductor device shown in FIG.
As a result of zone melting and recrystallization by the method, a single crystal silicon layer 13 is formed. At this time, even if the ZMR method is used,
Silicon concentration modulation layer 2 and second silicon concentration modulation layer 4
By providing the and, the crystal orientation plane of the single crystal silicon layer 13 can be changed to (1
A stable orientation surface other than the (00) plane can be obtained. In the semiconductor device shown in FIG. 4, for example, at the interface in contact with the silicon layer 3, the density of Si atoms in the first silicon concentration modulation layer 2 and the second silicon concentration modulation layer 4 is 6.78 × 10 ¹⁸ / cm 3. ^{With a} thickness of about ² , a single crystal silicon layer 13 having a (100) crystal orientation plane can be stably obtained, and at the interface in contact with the silicon layer 3, the first silicon concentration modulation layer can be obtained. 2, the density of Si atoms in the second silicon concentration modulation layer 4 is 7.83 × 10
If it is about ¹⁸ pieces / cm ² , the single crystal silicon layer 13
As a material having a (111) crystal orientation, a stable crystal can be obtained. Therefore, in the semiconductor device of FIG. 8, the single crystal silicon layer 13 is formed on the substrate 1 by using quartz glass (or S
Even if an amorphous substrate such as an iO ₂ layer) is used and is manufactured by the ZMR method, it is possible to stably obtain a crystal orientation plane other than the (100) plane, and control it to a desired crystal orientation plane. It is formed well.

In the above example, the single crystal silicon layer 13
In the above, the case of controlling the (100) plane and the (111) plane as two types of orientation planes was described. However, by changing the density of Si atoms in the silicon concentration modulation layer and the like, any desired orientation plane other than the above two types It is also possible to control to.

Further, in the above example, the first and second silicon concentration modulation layers 2 and 4 have a predetermined Si atom concentration secured at the interface with the silicon layer 3 (or the single crystal silicon layer 13). It suffices if there is no particular limitation on these thicknesses. Further, the second silicon concentration modulation layer 4
Although the crystal orientation plane of the single crystal silicon layer 13 can be controlled more stably and surely by providing the above, the second silicon concentration modulation layer 4 need not necessarily be provided depending on the case. good.

FIG. 9 is a diagram showing another example of the structure of a semiconductor device to be subjected to a single crystallization process by the ZMR method. In FIG. 9, the same parts as those in FIG. 4 are designated by the same reference numerals. With reference to FIG. 9, the semiconductor device includes a substrate 1
The first silicon concentration modulation layer 22, the silicon layer 23 to be single-crystallized by the ZMR method, the second silicon concentration modulation layer 24, and the surface protection layer 5. By the way, in the semiconductor device of FIG. 9, the first silicon concentration modulation layer 22 is formed by a method similar to that of the first silicon concentration modulation layer 2 of FIG. 4, but at that time, the interface with the silicon layer 23 is formed. Where the density of Si atoms in is two
2a and 22b are different from each other. The second silicon concentration modulation layer 24 is also formed by a method similar to that of the second silicon concentration modulation layer 4 of FIG. 4, but at this time, the density of Si atoms at the interface with the silicon layer 23 is The two portions 24a and 24b corresponding to the portions 22a and 22b of the first silicon concentration modulation layer 22 are different from each other. More specifically, the portions 22a and 24a of the first and second silicon concentration modulation layers 22 and 24 have a Si atom density of, for example, 6.78 × 10 ¹⁸ atoms / cm ² at the interface with the silicon layer 23. And the first and second silicon concentration modulation layers 22, 2
The fourth portions 22b and 24b have a Si atom density of, for example, 7.83 × 10 ¹⁸ atoms / cm ² at the interface with the silicon layer 23.

FIG. 10 shows the silicon layer 2 of the semiconductor device of FIG.
It is a figure which shows the structural example of the semiconductor device as a result of carrying out zone melting recrystallization of 3 by the ZMR method. Referring to FIG.
The silicon layer 23 of the semiconductor device shown in FIG. 9 is a single crystal silicon layer 3 as a result of zone melting and recrystallization by the ZMR method.
It becomes 3. At this time, the first and second silicon concentration modulation layers 2
The Si atom density of the portions 22a and 24a of 2, 24 is 6.7.
Since it is 8 × 10 ¹⁸ pieces / cm ² , these portions 22a,
A portion 33a of the single crystal silicon layer 33 corresponding to 24a
Is formed with the crystal orientation plane as the (100) plane. On the other hand, the Si atom density of the portions 22b and 24b of the first and second silicon concentration modulation layers 22 and 24 is 7.83 × 10 ¹⁸ /
Since it is cm ² , the portion 33b of the single crystal silicon layer 33 corresponding to these portions 22b and 24b is formed with the crystal orientation plane as the (111) plane. As described above, in the semiconductor device of FIG. 10, the single crystal silicon layer 33 is formed on the same substrate 1.
The portions 33a and 33b having different orientations are formed above.

In the above example, two different orientation planes,
That is, the single crystal silicon layer 33 is formed so as to be composed of two parts having the (100) plane and the (111) plane.
The silicon concentration modulation layer is further subdivided into
By making the density of i atoms different, the single crystal silicon layer 33 can be easily formed as one having two or more portions having different orientations on the same substrate 1.

Further, in the above example, the first and second silicon concentration modulation layers 22 and 24 have a predetermined Si at the interface with the silicon layer 23 (or the single crystal silicon layer 33).
It suffices that the atomic concentration is secured, and there is no particular limitation on the thickness thereof. Further, by providing the second silicon concentration modulation layer 24, the single crystal silicon layer 33
Although the crystal orientation planes of the respective portions 33a and 33b can be controlled more stably and surely, the second silicon concentration modulation layer 24 may not necessarily be provided depending on the case.

Based on the semiconductor device shown in FIGS. 8 and 10, a semiconductor device such as a thin film transistor can be formed. At this time, in the semiconductor device shown in FIGS. 8 and 10, the single crystal silicon layer 13,
Since the crystal orientation plane of 33 can be arbitrarily selected,
According to the present invention, it is possible to provide a semiconductor device having a crystal orientation plane according to the characteristics of the semiconductor device to be formed. Further, in the semiconductor device of FIG. 10, since the single crystal silicon layers 33 having different crystal orientation planes are formed on the same substrate, a semiconductor device having higher performance characteristics can be easily formed by using this semiconductor device. It becomes possible to do. In the semiconductor device of FIGS. 8 and 10, the surface protection layer 5 may be removed as needed in the process of forming the semiconductor device.

[0031]

EXAMPLE An example of the present invention will be described below with reference to FIG. In FIG. 11, the substrate 41 has a thickness of 1.6 mm
The transparent quartz glass substrate of was used. After cleaning the substrate 41 by a conventional method, the first silicon concentration modulation layer 42 was formed on the surface of the substrate 41 by the ion implantation method. Next, a polycrystalline silicon thin film was formed as a silicon layer to be single-crystallized by the ZMR method using low pressure chemical vapor deposition (LPCVD method) using silane gas (SiH ₄ ) as a raw material. The film thickness was 3500Å. Thereafter, this polycrystalline silicon thin film was formed into a stripe-shaped silicon layer 43 having a width of 100 μm by a photolithography method.
The stripe interval was processed to 10 μm.

Then, a second silicon concentration modulation layer 44 was formed on the striped polycrystalline silicon thin film 43 by the following procedure. That is, first, silane (SiH ₄ )
Pressure chemical vapor deposition (L) using thermal decomposition of oxygen and oxygen (O ₂ )
Forming a SiO ₂ layer of 2000 Å using PCVD method,
Silicon ion is injected into this layer by the ion injection method,
The second silicon concentration modulation layer 44 was formed. The conditions for forming the SiO ₂ film at this time were that the silane / oxygen gas ratio was 2/5.
(25 ° C., 1 atm conversion), the film forming pressure was 0.2 Torr, and the film forming temperature was 430 ° C.

Next, the second silicon concentration modulation layer 44 is formed.
A surface protective layer was formed on the above by the following procedure. That is,
Similar to the case of forming the second silicon concentration modulation layer, first, a SiO ₂ layer is formed by using low pressure chemical vapor deposition (LPCVD method) using thermal decomposition of silane (SiH ₄ ) and oxygen (O ₂ ). The (first surface protective layer) 45 was formed in a thickness of 1.6 μm. The film forming conditions were a silane / oxygen gas ratio of 2/5 (25 ° C., converted to 1 atm), a film forming pressure of 0.2 Torr, and a film forming temperature of 430 ° C. Under these conditions, it was possible to form a silicon oxide film, which was substantially recognized as SiO ₂ by infrared spectroscopy or the like. Then, a Si ₃ N ₄ layer (second surface protection layer) 46 is formed on the SiO ₂ layer by a high frequency sputtering method to a thickness of 2000.
Å The film was formed. The film forming conditions were a sintering target of SiN as a target material, a mixing ratio of 1: 1 in an N ₂ gas atmosphere, a pressure of 5 × 1/10 ³ Torr, and a high frequency power density of 3 W / cm ² . Under these conditions, a silicon nitride film, which is substantially recognized as Si ₃ N ₄ by infrared spectroscopy or the like, was obtained. After forming the semiconductor device 102 as described above, the stripe-shaped silicon layer 43 of the semiconductor device 102 was single-crystallized by using the ZMR method. Figure 12 is ZM
It is a schematic diagram of a melt recrystallization apparatus which performs single crystallization by R method. In FIG. 12, reference numeral 101 denotes a sample stage having a heater incorporated therein, which can be moved in the y direction at an arbitrary speed by a bolt screw 110 and a motor 109. Further, 103 is a semiconductor device formed according to the above procedure, that is, a carbon rod heater that gives a heat amount for melting the silicon layer 43 of the sample 102, and is arranged on the sample 102 at an equal distance from the sample surface. There is. The carbon rod-shaped heater 103 has a shape so that the temperature of the molten silicon portion falls within a temperature range of ± 0.5 ° C. when the silicon layer 43 on the substrate 41 of the sample 102 is melted by the heating. It has been processed. Also,
Reference numeral 104 denotes a non-contact thermometer, which is arranged so as to detect the temperature of the molten silicon portion formed on the sample 102. A temperature signal is output from the thermometer 104, and the temperature signal is transmitted to the heater temperature control circuit 106 via the temperature detection circuit 105. The heater temperature control circuit 106 is made of carbon according to the temperature signal. By controlling the heater power source 107 of the rod-shaped heater 103, the temperature of the molten silicon portion is kept constant within a range of ± 0.5 ° C. through melting and recrystallization. Using the apparatus having such a structure as shown in FIG. 12, the sample 102 was recrystallized. At that time, the sample 10 was made so that the stripes of the stripe-shaped silicon layer 43 were orthogonal to the carbon rod-shaped heater.
2 is placed on the sample stage 101, and the motor 109
The zone melt recrystallization was performed from one end to the other end of the sample 102 by driving the. The conditions for recrystallization are the substrate heating temperature 9 by the heater of the sample stage 101.
The temperature was 00 ° C., the moving speed of the sample was 0.1 mm / sec, and the temperature of the molten silicon portion was 1425 ° C.

The crystal orientation of the single crystal silicon layer obtained by changing various conditions of silicon ion implantation in the first and second silicon concentration modulation layers 42 and 44 of the sample 102 is determined by the X-ray diffraction and the etch pit grid method. The following table shows the results evaluated by. As you can see from the table below,
By properly setting the implantation conditions of the silicon ions to be implanted into the silicon concentration modulation layers 42 and 44 of (10
A single crystal silicon film having a (0) plane orientation and a (111) plane orientation could be obtained.

[0035]

[Table 1]

[0036]

As described above, according to the invention of claim 1, the first silicon concentration modulation layer is provided between the substrate and the silicon layer to be single-crystallized, and the first silicon concentration modulation layer is provided. At the interface of the silicon concentration modulation layer in contact with the silicon layer, the first silicon concentration modulation layer is provided with a predetermined silicon atom concentration necessary for controlling the crystal orientation plane when the silicon layer is single-crystallized. Therefore, when the silicon layer is single-crystallized, the crystal orientation plane of the single-crystal silicon layer can be stably and surely controlled to any desired one.

According to the second aspect of the present invention, a second silicon concentration modulation layer is further provided on the side of the silicon layer opposite to the first silicon concentration modulation layer, and the second silicon concentration modulation layer is provided. At the interface of the layer in contact with the silicon layer,
Since the predetermined silicon atom concentration necessary for controlling the crystal orientation plane when the silicon layer is single-crystallized is given to the second silicon concentration modulation layer, when the silicon layer is single-crystallized, The crystal orientation plane of the single crystal silicon layer can be controlled more stably and more reliably by any desired one.

According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, the silicon layer has the first and second silicon concentration modulation layers at the time of single crystallization. Since it has a crystal orientation plane according to the silicon atom concentration, it is possible to provide a semiconductor device having an optimal crystal orientation plane according to the characteristics of a semiconductor device to be manufactured.

According to a fourth aspect of the invention, in the semiconductor device according to the first or second aspect, the first and second silicon concentration modulation layers have different silicon atom concentrations at the interface in contact with the silicon layer. Therefore, when the silicon layer is single-crystallized, it is possible to easily form a plurality of single-crystal silicon portions having different crystal orientation planes on the same substrate.

According to a fifth aspect of the present invention, in the semiconductor device according to the fourth aspect, the silicon layer is formed into the first and second silicon concentration modulation layers at the time of single crystallization. Since they have different crystal orientation planes corresponding to a plurality of portions, it is possible to form a higher performance semiconductor device based on this semiconductor device.

According to the invention of claim 6, the step of providing the first silicon concentration modulation layer on the substrate having at least the surface layer made of silicon oxide, and the step of providing the first silicon concentration modulation layer on the substrate. Since it has a step of forming a layer of amorphous silicon or polycrystalline silicon and a step of converting the layer of amorphous silicon or polycrystalline silicon into a single crystal silicon layer by a zone melting recrystallization method, any desired A semiconductor device having a crystal orientation plane can be formed.

[Brief description of drawings]

1A is a diagram showing an outline of a radial distribution function of amorphous SiO ₂ , and FIG. 1B is a two-dimensional view of amorphous SiO ₂ inferred from the radial distribution function shown in FIG. It is a figure which shows an expression.

2A and 2B are views for explaining the arrangement of Si atoms on the (100) plane of a silicon crystal.

3A and 3B are views for explaining the arrangement of Si atoms on the (111) plane of a silicon crystal.

FIG. 4 is a diagram showing a configuration example of a semiconductor device of the present invention in which a single crystallization process is performed by a ZMR method.

FIG. 5 is a plan view showing an example of a planar arrangement of silicon layers of the present invention.

FIG. 6 is a plan view showing an example of a planar arrangement of silicon layers of the present invention.

FIG. 7 is a plan view showing an example of a planar arrangement of silicon layers of the present invention.

8 is a diagram showing a configuration example of a semiconductor device of the present invention as a result of zone melting and recrystallization of a silicon layer of the semiconductor device shown in FIG. 4 by a ZMR method.

FIG. 9 is a diagram showing another configuration example of the semiconductor device of the present invention in which single crystallization processing is performed by the ZMR method.

FIG. 10 is a diagram showing a ZMR method for a silicon layer of the semiconductor device shown in FIG.
It is a figure which shows the other structural example of the semiconductor device of this invention as a result of carrying out zone melting recrystallization by the method.

FIG. 11 is a configuration diagram of an embodiment of a semiconductor device of the present invention.

FIG. 12 is a schematic view of a melt recrystallization apparatus for manufacturing the semiconductor device of the present invention.

13A and 13B are diagrams for explaining the ZMR method.

FIG. 14 is a diagram for explaining the progress of zone melting recrystallization.

[Explanation of symbols]

 1 Substrate 2,22 First Silicon Concentration Modulation Layer 3,23 Silicon Layer 4,24 Second Silicon Concentration Modulation Layer 5 Surface Protection Layer 13,33 Single Crystal Silicon Layer 101 Internal Heater 102 Sample for Melt Recrystallization 103 bar heater 104 thermometer 105 temperature detection circuit 106 heater temperature control circuit 107 heater power supply 108 heater power supply and temperature control circuit 109 motor 110 ball screw

Claims (6)

[Claims] 1. A first silicon concentration modulation layer, comprising: a substrate, a silicon layer to be single-crystallized, and a first silicon concentration modulation layer provided between the substrate and the silicon layer. Is a semiconductor device having a predetermined silicon atom concentration necessary for controlling a crystal orientation plane when the silicon layer is single-crystallized at an interface in contact with the silicon layer. 2. The semiconductor device according to claim 1, wherein a second silicon concentration modulation layer is further provided on the side of the silicon layer opposite to the first silicon concentration modulation layer, and the second silicon concentration modulation layer is provided. The silicon concentration modulation layer has a predetermined silicon atom concentration necessary for controlling a crystal orientation plane when the silicon layer is single-crystallized at an interface in contact with the silicon layer. apparatus. 3. The semiconductor device according to claim 1, wherein the silicon layer is single-crystallized,
A semiconductor device having a crystal orientation plane according to the silicon atom concentration of the first and second silicon concentration modulation layers. 4. The semiconductor device according to claim 1, wherein the first and / or second silicon concentration modulation layer includes a plurality of portions having different silicon atom concentrations at an interface in contact with the silicon layer. A semiconductor device characterized by being present. 5. The semiconductor device according to claim 4, wherein when the silicon layer is single-crystallized, the first
And / or semiconductor devices having different crystal orientation planes corresponding to the plurality of portions of the second silicon concentration modulation layer. 6. A step of providing a first silicon concentration modulation layer on a substrate having at least a surface formed of an insulating material, and a layer of amorphous silicon or polycrystalline silicon on the first silicon concentration modulation layer. And a step of converting an amorphous silicon or polycrystalline silicon layer into a single crystal silicon layer by a zone melting recrystallization method.