JP2003188170A - Method for producing semiconductor oxide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an oxide film to bury into a semiconductor, e.g. an oxide film to bury into silicon, in which the oxide film can be made thin while maintaining uniformity of the film thickness and the performance as an insulation film. <P>SOLUTION: In a first layer forming process (1) for epitaxially growing silicon on a single crystal silicon substrate 1, silicon is grown epitaxially while adding oxygen to such an extent as the single crystallinity of silicon is not collapsed by growing silicon epitaxially on the single crystal silicon substrate 1 in oxygen atmosphere. Subsequently, a single crystal silicon film 3 is formed in a second layer forming process (2) by stopping introduction of oxygen and growing only silicon epitaxially on a silicon film 2 containing oxygen. Subsequently, a silicon oxide film 4 is formed in an oxidation process (3) by heat treating a semiconductor layer thus formed in an oxidizing atmosphere. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a buried oxide film on a semiconductor used as a semiconductor device, for example, a buried oxide film on silicon.

[0002]

2. Description of the Related Art LSI (Large Sc
In the technology of ale integration), miniaturization and high integration of LSI are progressing year by year in order to meet the demand for large capacity. Especially in the near future VLSI,
100-nm gate length MOSFET (Metal-Oxide-Semi
Since the conductor field effect transistor) is adopted, it is required to further thin the gate oxide film, which is an insulating film necessary for suppressing the short channel effect, and to make the device structure complicated. For such a gate oxide film, in particular, single crystal silicon is used to form a silicon oxide film.
Hereinafter, the case where single crystal silicon is used will be exemplified.

Research has been conducted on the use of an SOI (Silicon-On-Insulator) structure substrate as a semiconductor device to meet the demand for a thinner gate oxide film.

Among these, SIMOX (Separation by IMplanted OXyglen) in which oxygen ions are implanted into a silicon substrate and oxidized to form a buried oxide film.
Techniques such as a bonding technique for forming a buried oxide film by bonding substrates to each other after forming an oxide film have been developed.

[0005]

However, in the SIMOX technique, it is necessary to ion-implant all the oxygen necessary for the reaction, and the oxygen ion-implanting process takes a long time.
In addition, in this technique, the oxide film can usually be made thinner by lowering the concentration of oxygen ions to be implanted, but there is a limit to reducing the ion concentration to make the oxide film thinner. However, the uniformity of the film thickness cannot be maintained.

On the other hand, the bonding technique requires a step of bonding another silicon substrate on the oxide film after forming the oxide film. If the oxide film to be formed is too thin, bending of the oxide film is likely to occur due to adjustment of the pressing force at the time of bonding. Due to the occurrence of the bending, the film thickness uniformity of the oxide film is deteriorated and the bonding is not performed well, so that the reproducibility is lowered. Further, it is known that the performance as an insulating film of the oxide film is deteriorated as compared with that before the bonding by performing the bonding after forming the oxide film. Further, this phenomenon becomes more remarkable as the oxide film thickness is made thinner.

As described above, there is a limit to thinning the oxide film by any of the above methods, and it is difficult to form a buried oxide film that can meet the demand for thinning the gate oxide film.

The present invention has been made to solve the above-mentioned problems of the prior art. A buried oxide film for a semiconductor, which can be thinned while maintaining film thickness uniformity and performance as an insulating film, for example, An object of the present invention is to provide a method for manufacturing a buried oxide film in silicon.

[0009]

A method for producing a semiconductor oxide film according to the present invention is a method for producing a single crystal semiconductor oxide film used as a semiconductor element, wherein a semiconductor material is formed on a single crystal semiconductor substrate in an oxygen atmosphere. A first layer forming step of forming an oxygen-containing semiconductor film containing oxygen while retaining the single crystallinity of the semiconductor material by epitaxial growth, and a single crystal semiconductor film is further epitaxially grown on the oxygen-containing semiconductor film. A second layer forming step of forming and an oxidizing step of oxidizing the formed oxygen-containing semiconductor film by heat treatment in an oxidizing atmosphere after the first layer forming step and the second layer forming step. It is a thing.

In the method for producing a single crystal semiconductor oxide film of the present invention, in the first layer forming step of epitaxially growing a semiconductor material on a single crystal semiconductor substrate, the semiconductor material is epitaxially grown on the single crystal semiconductor substrate in an oxygen atmosphere. Thus, the semiconductor material is epitaxially grown while containing oxygen to the extent that the single crystallinity of the semiconductor material is not destroyed. Single crystallinity means that the crystals have the same orientation (crystal orientation) and the lattice spacing is the same value as that of the single crystal of the semiconductor only. The crystal orientation is closely related to electrical characteristics and directly relates to the performance as a semiconductor device. Here, epitaxial growth means that when a substance is vaporized or evaporated in a vacuum and is adsorbed and grown on the surface of the underlying single crystal, the growth surface and the axial direction are the same as those of the underlying crystal due to the influence of the underlying crystal. It utilizes the phenomenon that a single crystal thin film is formed. In such an epitaxial growth process, lattice defects are formed in advance by including oxygen in the semiconductor film to be oxidized.

Subsequently, in the step of forming the second layer, the introduction of oxygen is stopped and only the semiconductor substance is epitaxially grown on the oxygen-containing semiconductor film to form a single crystal semiconductor film. Since the semiconductor material grown in the first layer forming step retains single crystallinity, the single crystal semiconductor can be easily grown subsequently.

After that, in the oxidation step, the formed semiconductor layer is heat-treated in an oxidizing atmosphere to preferentially oxidize the oxygen-containing semiconductor film having many lattice defects to form a semiconductor oxide film. Note that the oxidizing atmosphere is an atmosphere containing oxygen, and includes an atmosphere in which oxygen is partially divided by another substance and an atmosphere containing only oxygen.

As described above, oxygen is contained in the oxidation step by utilizing the property that the lattice defects are formed by including oxygen in the single crystal semiconductor film in advance and the region having many lattice defects is preferentially oxidized. It is possible to oxidize only the regions that are open. Thereby, the film thickness uniformity of the semiconductor oxide film can be maintained. Further, by including oxygen in advance, it is possible to efficiently promote the oxidation and make it difficult for the interstitial semiconductor atoms to remain. As a result, the reliability of the insulating film can be maintained.

Further, since the lattice defects are generated in advance in the region to be oxidized, the oxidation rate can be increased.
Similarly, the oxidation temperature can be kept low. Therefore, the redistribution of impurities can be suppressed, the change in impurity concentration can be suppressed, and the reliability of the gate oxide film as an insulating film can be maintained. Further, since only the oxygen-containing semiconductor film is transformed into a semiconductor oxide film, the film thickness of the semiconductor oxide film can be controlled by controlling the film thickness of the oxygen-containing semiconductor film, and the gate oxide film can be easily formed into a thin film. Can be converted.

Preferably, the oxygen concentration in the oxygen atmosphere in the first layer forming step is adjusted to be lower than the oxygen concentration in the oxidizing atmosphere in the oxidizing step.

Oxygen contained in the oxygen-containing semiconductor film is
It does not contain the amount of oxygen necessary for forming the oxide film, but contains a much smaller amount of oxygen. This is because there is a limit to the amount of oxygen that can be introduced while maintaining single crystallinity. By making the oxygen concentration in the oxygen atmosphere in the first layer forming step lower than the oxygen concentration in the oxidizing atmosphere in the oxidizing step, oxygen is contained in the oxidizing step while maintaining the single crystallinity of the semiconductor material in the epitaxial growth process. The oxygen-containing semiconductor film capable of preferentially oxidizing the existing region can be easily formed.

Preferably, the epitaxial growth in the first layer forming step is performed by a molecular beam epitaxy method. Molecular beam epitaxy (MBE; Molecu
larBeam Epitaxy method) is a method of forming an epitaxial growth layer on a substrate by injecting a molecular beam or an atomic beam into the substrate in an ultrahigh vacuum of about 10 ^-10 Torr, which is a highly controlled vacuum deposition method. is there. Since this growth method has a lower growth temperature than other epitaxial growth methods,
Since the growth rate is slow, it is possible to control the molecular beam irradiation and the like in the epitaxial growth with high accuracy, and it is suitable for controlling the film thickness at an extremely thin monoatomic layer level.

As described above, the oxygen-containing semiconductor film is formed and oxidized by using the MBE method capable of controlling the film thickness at an extremely thin monoatomic layer level. A buried oxide film for an extremely thin gate oxide film can be formed while maintaining the performance of the oxide film as an insulating film. The MBE method can also be used in the second layer forming step.

Preferably, the single crystal semiconductor substrate is a single crystal silicon substrate, and silicon is epitaxially grown in the first layer forming step and the second layer forming step.

Silicon is one of the most commonly used materials for semiconductor devices. In addition, single crystal silicon is
Since silicon atoms are regularly arranged, the quality as a semiconductor device is stable, and it is effective as a material for forming a gate oxide film.

Preferably, a striped laminated structure is formed on the single crystal semiconductor substrate by repeating the first layer forming step, the second layer forming step and the oxidizing step.

At present, a diffraction grating is used as an element for achieving high functionality of optical pickups such as CDs and DVDs and light guide plates such as small liquid crystal backlight panels for mobile phones and the like, which are small and highly efficient. . The diffraction grating is a glass plate or a metal plate in which precise grooves are formed at equal intervals, and obtains a spectrum of light by utilizing the diffraction phenomenon of light. There are hundreds to thousands of grooves per mm.

However, in the diffraction grating, a pitch (grating constant) similar to the wavelength of the light used is required,
When a submicron-order structure is required in the future due to a demand for higher performance of the optical pickup, it is difficult to carve such a fine pitch. Therefore, it is desired to easily manufacture a diffraction grating having an extremely small grating constant.

According to the present invention, the oxygen-containing silicon film is formed by epitaxial growth in the first layer forming step, and the single crystal silicon film is formed by epitaxial growth in the second layer forming step. In the oxidation process,
Only the oxygen-containing silicon film that is the first layer is oxidized.

Since only the oxygen-containing silicon film which is the first layer is oxidized in the oxidation step, the single crystal silicon film which is the second layer still retains the single crystallinity.
Therefore, the oxygen-containing silicon film can be epitaxially grown again on the second layer before and after the oxidation step. In this way, it is possible to form a striped laminated structure on the single crystal silicon substrate, which is composed of a silicon oxide film and single crystal silicon and has excellent film thickness uniformity and excellent light reflectivity in the oxide film. By forming such a striped laminated structure, it is possible to form a reflection diffraction grating having an extremely small lattice constant.

In such a diffraction grating, a pitch (grating constant) about the same as the wavelength of the light used is required, and for example, a structure of submicron order C is required.
It is possible to achieve high functionality of an optical pickup such as a D or DVD, and miniaturization and high efficiency of a light guide plate such as a small liquid crystal backlight panel of a mobile phone.

[0027]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to the accompanying drawings. Note that in this embodiment mode, the case where a silicon oxide film is formed by growing silicon over a single crystal silicon substrate is described as an example; however, the same semiconductor substance as the substrate is formed over another single crystal semiconductor substrate. It can be manufactured similarly by growing it.

FIG. 1 is a conceptual diagram of a method for manufacturing a silicon oxide film according to the first embodiment of the present invention. In the method of manufacturing the silicon oxide film 4 in the present embodiment, the silicon is epitaxially grown on the single crystal silicon substrate 1 in an oxygen atmosphere, so that the oxygen-containing silicon film containing oxygen while maintaining the single crystallinity of the silicon. 2 is formed, and an oxidation step of oxidizing the formed oxygen-containing silicon film 2 by heat treatment in an oxidizing atmosphere is performed. Note that FIG.
Since is a conceptual diagram, the component ratios of oxygen and silicon, the bonding state, etc. in this figure do not show the actual state.

First, the first layer forming step of this embodiment will be described. In the first layer forming step, as shown in FIG.
Silicon is epitaxially grown on a previously prepared single crystal silicon substrate 1 as shown in (a). Here, the epitaxial growth means that when a substance is vaporized or evaporated in a vacuum and adsorbed and grown on the surface of the underlying single crystal, the growth surface and the axial direction are matched with those of the underlying crystal under the influence of the underlying crystal. It utilizes the phenomenon that a single crystal thin film is formed. As a method for producing a single crystal utilizing this epitaxial growth, there are a chemical vapor deposition method (CVD method), a molecular beam epitaxy method (MBE method), a sputtering method and the like.

The epitaxial growth process in this embodiment is performed in an oxygen atmosphere. At this time, the oxygen concentration is adjusted, and silicon is epitaxially grown on the single crystal silicon substrate 1 while containing oxygen in an amount that does not destroy the single crystallinity of silicon.

In this way, as shown in FIG. 1B, the oxygen-containing silicon film 2 which maintains the single crystallinity of silicon as the whole film is formed on the single crystal silicon substrate. At this time, oxygen contained in the oxygen-containing silicon film 2 is
It does not contain the amount of oxygen necessary for forming the oxide film, but contains a much smaller amount of oxygen. This is because there is a limit to the amount of oxygen that can be introduced while maintaining single crystallinity. By using a small amount of oxygen, the region containing oxygen is preferentially oxidized in the oxidation step while maintaining the single crystallinity of silicon in the epitaxial growth, so that silicon as shown in FIG. The buried oxide film 4 can be formed.

Therefore, in the present embodiment, the first
The oxygen concentration in the oxygen atmosphere in the layer forming step is made lower than the oxygen concentration in the oxidizing atmosphere in the oxidizing step.
This makes it possible to easily form the oxygen-containing silicon film 2 capable of preferentially oxidizing the region containing oxygen in the oxidation step while maintaining the single crystallinity of silicon in the epitaxial growth. In the present embodiment, the oxygen-containing silicon film 2 is formed in an oxygen atmosphere having an oxygen concentration of about 1 × 10 ¹⁹ cm ^-2 .

Next, the second layer forming step in this embodiment will be described. Silicon is epitaxially grown on the oxygen-containing silicon film 2 that is the first layer. In the second layer forming step, normal epitaxial growth is performed without introducing oxygen. Since single crystallinity is maintained in the oxygen-containing silicon film 2, the single crystal silicon film 3 can be formed by epitaxially growing silicon on the oxygen-containing silicon film 2.

In the present embodiment, the epitaxial growth process in the first layer forming process and the second layer forming process is performed by the molecular beam epitaxy method. Molecular beam epitaxy (MBE)
Method) is a method in which a molecular beam or an atomic beam is incident on a substrate in an ultrahigh vacuum of about 10 ⁻¹⁰ Torr to form an epitaxial growth layer on the substrate, which is a highly controlled vacuum vapor deposition method. Since this growth method has a slower growth rate than the other epitaxial growth methods, the growth rate is slow, so the accuracy of oxidation can be improved, and it is suitable for controlling the film thickness at the extremely thin monoatomic layer level. Is characterized by.

FIG. 2 shows an M used in this embodiment.
It is the schematic of a BE apparatus. The MBE apparatus is a molecular beam cell for holding a vacuum, a chamber 11 for performing a growth operation, a vapor deposition material for each type, heating each vapor deposition material with a heater to vaporize it, and irradiating it toward a substrate 1. 12
a to 12d and shutters 13a to 1 provided on the chamber 11 side of each of the molecular beam cells 12a to 12d for selecting a vapor deposition material to be irradiated and controlling the irradiation time.
3d, a gas inlet 14 for introducing a gas such as oxygen into the chamber 11, and a substrate holder 15 provided with a heater for supporting the substrate 1 and controlling the substrate temperature.
An electron gun 16 for electron beam diffraction, and a fluorescent screen 17 for displaying a pattern diffracted by the electron gun 16.
It is equipped with and.

The single crystal silicon substrate 1 is placed on the substrate holder 15 in the chamber 11 and the inside of the chamber 11 is set to 10 ⁻¹⁰ Tor.
Keep in an ultra-high vacuum state of about r. The substrate holder 15 has
A substrate heating heater is provided to heat the single crystal silicon substrate 1 to an optimum temperature at which silicon easily grows. Since the growth temperature in the MBE method can be made lower than that in the usual epitaxial growth method, the single crystallinity can be easily maintained. On the other hand, molecular beam cell 12
A vapor deposition material can be stored in each of a to 12d. In the present embodiment, since the vapor deposition material is only silicon, the molecular beam cell 12a contains silicon.

The molecular beam cell 12a heats silicon by a heater provided therein to vaporize the silicon. The vaporized silicon is introduced into the chamber 11 by opening the shutter 13a on the side of the chamber 11 of the molecular beam cell 12a. Since the inside of the chamber 11 is maintained in an ultra-high vacuum, the silicon introduced into the chamber 11 is the first
In the layer forming step, a substance other than oxygen described later,
In the second layer forming step, it can be grown on the single crystal silicon substrate 1 without colliding with other substances including oxygen. Further, since the shutter 13a can be opened and closed arbitrarily, the film thickness, the growth rate, etc. can be arbitrarily controlled by opening and closing the shutter 13a.

The gas introduction port 14 is for introducing oxygen into the chamber 11 so that the silicon film grown in the first layer forming step contains oxygen. When oxygen is introduced into the chamber 11, the internal pressure rises,
That is, the degree of vacuum decreases. In other words, the concentration of oxygen introduced from the gas inlet 14 can be adjusted by adjusting the degree of vacuum. Specifically, the amount of oxygen introduced is automatically controlled by opening and closing the shutter provided in the gas inlet 14 while measuring the degree of vacuum. As described above, the oxygen concentration in the first layer forming step is adjusted to a concentration that does not impair the single crystallinity of the grown silicon.

In the MBE apparatus, the reflection type high-energy electron diffraction (RHEED; Reflective H) is used during the growth of the semiconductor film.
Since in-situ observation of monoatomic layer growth by igh energy electron diffraction can be performed, a more accurate oxygen-containing silicon film can be formed. This RHEED
Is caused by causing an electron beam to be incident on the substrate 1 at an extremely shallow angle by the electron gun 16 and applying the electron beam diffracted according to the state of atoms and molecules on the surface of the growth layer to the fluorescent screen 17 to emit light. , In-situ observation of changes in surface structure in real time.

As described above, the oxygen-containing silicon film 2 can be formed while adjusting the oxygen concentration and the growth rate of silicon to be epitaxially grown in the first layer forming step. In particular, by using the MBE device, it is possible to control the film thickness at the monatomic level while ensuring the film thickness uniformity of the oxygen-containing silicon film 2 and the reliability as an LSI device.

As described above, the oxygen-containing silicon film 2 and the single crystal silicon film 3 are formed by using the MBE method capable of controlling the film thickness at an extremely thin monoatomic layer level, and the oxygen-containing silicon film 2 is formed. By oxidizing only the region, an extremely thin silicon oxide film can be formed while maintaining the film thickness uniformity of the silicon oxide film 4 and the reliability of film quality deterioration.

Furthermore, by controlling the film thickness at the single atom level, the oxygen-containing silicon film 2 and the single crystal silicon film 3 can be made to have a film thickness corresponding to several atoms of silicon.
Such an oxygen-containing silicon film 2 for several atoms of silicon
By forming the single crystal silicon film 3 and the gate oxide film for several atoms of silicon having the silicon oxide film 4, it is possible to form a gate oxide film having very good performance as an LSI device. it can.

Next, the oxidation process of this embodiment will be described. In the oxidizing step, after the first layer forming step and the second layer forming step, the oxygen-containing silicon film 2 on the single crystal silicon substrate 1 formed in the first layer forming step is heat-treated in an oxidizing atmosphere. Oxidation is performed to form a silicon oxide film 4 as shown in FIG.

It is known that during the heat treatment, oxygen in the atmosphere is attracted to lattice defects formed in the oxygen-containing silicon film 2 and preferentially bonds with silicon in the oxygen-containing silicon film 2. Further, the single crystal silicon substrate 1 generally contains a very small amount of oxygen, but this minute amount of oxygen is also attracted to the lattice defects formed in the oxygen containing silicon film 2 and the oxygen containing silicon film is obtained. Bonds preferentially with the silicon in 2. Similarly, when a very small amount of oxygen is mixed in the second-layer single crystal silicon film 3, it will be attracted to the lattice defects formed in the oxygen-containing silicon film 2. In the present embodiment, since this property is utilized, only the region of the oxygen-containing silicon film 2 is formed so as to be transformed into the silicon oxide film 4.

As described above, oxygen is contained in the oxidation process by utilizing the property that the lattice defects are formed by preliminarily containing oxygen in the silicon semiconductor film and the region having many lattice defects is preferentially oxidized. Only the region can be oxidized. Thereby, the film thickness uniformity of the silicon oxide film 4 can be maintained. Further, by preliminarily containing oxygen, it is possible to efficiently promote the oxidation and make it difficult for the interstitial silicon atoms that deteriorate the insulating property to remain. As a result, the reliability of the insulating film can be maintained. Further, a very small amount of oxygen mixed in the single crystal silicon substrate 1 and the single crystal silicon film 3 is added to the oxygen-containing silicon film 2
Therefore, the interface between the single crystal silicon layer and the oxide film can be made clear, and a gate oxide film with better performance can be formed.

In the oxidation process, silicon carbide (Si
The semiconductor layer having the first layer and the second layer formed on the single crystal silicon substrate 1 is housed in an electric furnace using a tube made of C) and heated to be oxidized.

In this embodiment, the oxidation step is
It is carried out in an oxidizing atmosphere in which oxygen is partially divided by an inert gas such as argon or xenon. In the present embodiment, since oxygen-containing silicon film 2 is formed, oxygen is attracted into oxygen-containing silicon film 2 as described above. At this time, when the oxygen is oxidized in a high-concentration oxygen atmosphere, oxygen in the atmosphere is excessively attracted, so that oxygen is diffused toward the single crystal silicon substrate 1 or the single crystal silicon film 3 on the contrary. May be caused. Therefore, in order to reduce the oxygen concentration, the oxygen in the atmosphere is mixed with an inert gas such as argon or xenon, which does not affect the oxidation by heating, into the atmosphere to partial pressure. Oxygen concentration can be lowered by partial pressure with an inert gas that does not affect oxidation,
It is possible to suppress the outward diffusion phenomenon of oxygen attracted to the oxygen-containing silicon film 2.

Next, a second embodiment of the present invention will be described.

In the present embodiment, the striped laminated structure is formed on the single crystal silicon substrate 1 by repeating the first layer forming step, the second layer forming step and the oxidizing step in the first embodiment. To do.

Also in the present embodiment, the oxygen-containing silicon film 2 is formed by epitaxial growth in the first layer forming step, and the single crystal silicon film 3 is formed by epitaxial growth in the second layer forming step. In the oxidation step, the oxygen-containing silicon film 2 which is the first layer
Only the silicon oxide film 4 is formed by oxidation.

Since only the oxygen-containing silicon film 2 which is the first layer is oxidized in the oxidation step, the single crystal silicon film 3 which is the second layer still retains the single crystallinity. Therefore, the oxygen-containing silicon film 2 can be epitaxially grown again on the second layer before and after the oxidation step. In this way, a striped laminated structure is formed on the single crystal silicon substrate 1 that is excellent in the film thickness uniformity composed of the silicon oxide film 4 and the single crystal silicon layers 1 and 3 and the light reflectivity in the oxide film. Can be formed. By forming such a striped laminated structure, it is possible to form a reflection diffraction grating having an extremely small lattice constant.

FIG. 3 is a conceptual diagram showing a diffraction grating formed in the second embodiment of the present invention. As shown in FIG. 3, in the diffraction grating of the present embodiment, the silicon oxide film 4 that reflects the incident light reflects the incident light, and the single crystal silicon substrate 1 and the single crystal silicon film 3 diffract the incident light. Acts like.

The relationship between the distance (lattice constant) d between the single crystal silicon layers 1 and 3 when the reflected light appears strongly, the wavelength λ of the incident light, the incident angle α and the reflection angle β is as follows. Shown. d (sinα + sinβ) = mλ (m = ± 1, ± 2, ± 3
…)

From the above equation, the diffraction grating needs to have a pitch (grating constant) similar to the wavelength of the light used. In the present embodiment, since a diffraction grating having a lattice constant d of about several atoms can be formed, effective diffraction is possible even for light having a short wavelength λ of about several atoms. Light is obtained.

Therefore, for example, optical pickups such as CDs and DVDs, which are required to have a structure of the order of submicron, are highly functionalized, and light guide plates such as small liquid crystal backlight panels such as mobile phones are miniaturized and highly efficient. Can be achieved

[0056]

EFFECTS OF THE INVENTION Oxygen-containing regions are formed in the oxidation process by utilizing the property that lattice defects are formed by preliminarily containing oxygen in the single crystal semiconductor film, and the regions having many lattice defects are preferentially oxidized. Only can be oxidized. Thereby, the film thickness uniformity of the semiconductor oxide film can be maintained. Further, by including oxygen in advance, it is possible to efficiently promote the oxidation and make it difficult for the interstitial semiconductor atoms to remain. As a result, the reliability of the insulating film can be maintained.

Further, since the lattice defects are generated in advance in the region to be oxidized, the oxidation rate can be increased.
Similarly, the oxidation temperature can be kept low. Therefore, the redistribution of impurities can be suppressed, the change in impurity concentration can be suppressed, and the reliability of the gate oxide film as an insulating film can be maintained. Further, since only the oxygen-containing semiconductor film is transformed into a semiconductor oxide film, the film thickness of the semiconductor oxide film can be controlled by controlling the film thickness of the oxygen-containing semiconductor film, and the gate oxide film can be easily formed into a thin film. Can be converted.

On the other hand, it is possible to form a striped laminated structure composed of a silicon oxide film and single crystal silicon on the single crystal silicon substrate, which is excellent in film thickness uniformity and light reflectivity in the oxide film. By forming such a striped laminated structure, it is possible to form a reflection diffraction grating having an extremely small lattice constant.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a method for manufacturing a silicon oxide film according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an MBE device used in the present embodiment.

FIG. 3 is a conceptual diagram showing a diffraction grating formed in a second embodiment of the present invention.

[Explanation of symbols]

1 ... Single crystal silicon substrate 2 ... Oxygen-containing silicon film 3
… Single crystal silicon film 4… Silicon oxide film

Claims (5)

[Claims] 1. A method for producing a single crystal semiconductor oxide film used as a semiconductor device, wherein the semiconductor material retains single crystallinity by epitaxially growing the semiconductor material on a single crystal semiconductor substrate in an oxygen atmosphere. A first layer forming step for forming an oxygen-containing semiconductor film containing oxygen while forming a second layer forming step for forming a single crystal semiconductor film on the oxygen-containing semiconductor film by the epitaxial growth; and a first layer forming step. And after the second layer forming step,
And a step of oxidizing the formed oxygen-containing semiconductor film by heat-treating it in an oxidizing atmosphere. 2. The single crystal semiconductor oxide film according to claim 1, wherein the oxygen concentration in the oxygen atmosphere in the first layer forming step is lower than the oxygen concentration in the oxidizing atmosphere in the oxidizing step. Production method. 3. The method for producing a semiconductor oxide film according to claim 1, wherein the epitaxial growth in the first layer forming step is performed by a molecular beam epitaxy method. 4. The single crystal semiconductor substrate is a single crystal silicon substrate, and silicon is epitaxially grown in the first layer forming step and the second layer forming step. A method for manufacturing a semiconductor oxide film according to item 1. 5. The striped laminated structure is formed on the single crystal semiconductor substrate by repeating the first layer forming step, the second layer forming step, and the oxidizing step. A method for producing a semiconductor oxide film as described above.