JP6515318B2 - Method of manufacturing crystalline laminated structure and semiconductor device - Google Patents

Description

  The present invention relates to a method of manufacturing a crystalline laminated structure used for manufacturing a semiconductor device and a semiconductor device.

  Conventionally, transparent conductive films have been used as transparent electrodes for solar cells or as transparent electrodes for flat panel displays. In these applications, transparency is important in the visible region of wavelengths 400 nm to 800 nm, and tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide ( AZO) is known as a representative transparent conductive material.

Patent Document 1 discloses an ultraviolet transparent conductive film made of a Ga ₂ O ₃ crystal and containing at least one element of Sn, Ge, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W as a dopant. Can transmit blue light near 400 nm and ultraviolet light of shorter wavelength sufficiently, and it is a transparent electrode for ultraviolet light emitting devices, a transparent electrode for ultraviolet photovoltaic power generation, a transparent electrode for biomaterial analysis, charging for ultraviolet laser processing It is described that it is useful as a protective film etc. Moreover, according to Patent Document 1, it is described that the conductivity of the Ga ₂ O ₃ crystal can be expressed by adding an oxygen defect or a dopant element, and for Ga ₂ O ₃ and ZnGa ₂ O ₄ , Although it has been confirmed that a single crystal sample and a polycrystal sample can be used as a transparent conductive material, conventionally, it is described that it was not possible to make these into thin films and to impart transparent conductivity. .

Non-Patent Document 1 describes that the conductivity is increased by doping Ge or Ti into a Ga ₂ O ₃ single crystal. Non-Patent Document 2 describes that the conductivity is increased in the range of 10 ⁻⁹ to 38 Ω ⁻¹ cm ⁻¹ by doping the Ga ₂ O ₃ single crystal with Sn that is a group element.

Patent Document 2 describes that when Si, Hf, Ge, Sn, Ti, or Zr is doped into a Ga ₂ O ₃ -based single crystal, a low resistance film can be obtained. In the Ga ₂ O ₃ -based film, a dopant of a Group IV element has mainly been used for the purpose of improving the conductivity and decreasing the electrical resistance.

As another example, Patent Document 3 discloses a substrate with a β-Ga ₂ O ₃ single crystal film having a β-Ga ₂ O ₃ single crystal film grown on a large diameter sapphire substrate by liquid phase epitaxial method. In particular, lead oxide (PbO) or lead fluoride (PbF ₂ ) is used to melt β-Ga ₂ O ₃ polycrystals during film formation, and this is used as boron oxide (B ₂ O ₃ ) or by adding vanadium pentoxide (V 2 _{O 5),} it is described that can be inexpensive and produce β-Ga ₂ O ₃ single crystal film with a substrate having a β-Ga ₂ O ₃ single crystal film easily .

  However, in any of the techniques, carbon is mixed or the crystallinity is poor, and in particular, the controllability of the carrier concentration is not satisfactory. Therefore, carbon is not mixed and the crystallinity is also impaired. There is a need for a method that can easily control the carrier concentration.

Japanese Patent Laid-Open No. 2002-93243 JP, 2005-235961, A JP, 2013-028480, A JP, 2014-015366, A

TOMM, Y. et al., Floating zone growth of β-Ga 2 O 3: A new window material for optoelectronic device applications, Solar Energy Materials & Solar Cells, February 2001, Vol. 66, pp. 369-374 UEDA, N., et al., Synthesis and control of conductivity of ultraviolet transmitting β-Ga2O3 single crystals, Applied Physics Letters, June 30, 1997, Volume 70, Issue 26, pp. 3561-3563

An object of the present invention is to provide a method for producing a laminated structure having a β-Ga ₂ O ₃ -based film having a low half width and excellent semiconductor characteristics.

As a result of intensive studies to achieve the above object, the present inventors have surprisingly achieved that a β-Ga ₂ O ₃ -based film is formed by mist CVD using Ge or Si as a dopant. Not only was there almost no carbon that would be incorporated as a small amount as an impurity in the resulting film, but also the half width of the thin film was lowered. Such a thing was unexpected for the present inventors.
In addition, the present inventors formed a β-Ga ₂ O ₃ based film using β-Ga ₂ O ₃ as a substrate in the same manner as described above, and the obtained film substantially contained carbon as an impurity. The inventors have obtained various findings such that the film is not contained and the half width is also lowered, and it has been found that such a film forming method can solve the above conventional problems at once.

  In addition, after obtaining the above-mentioned findings, the present inventors repeated studies to complete the present invention.

That is, the present invention relates to the following inventions.
[1] Raw material fine particles generated by micronizing the raw material solution are supplied to the film forming chamber by the carrier gas, and a crystalline oxide having a β-gallia structure on the base substrate disposed in the film forming chamber as a main component As a method of manufacturing a crystalline layered structure forming a crystalline oxide thin film, wherein Ge or Si is used as a dopant to perform a doping process when the crystalline oxide thin film is formed. The method for producing a crystalline laminate structure, wherein the crystalline oxide thin film contains germanium or silicon but does not substantially contain carbon and has a half width of 50 arcsec or less.
[2] The method according to the above [1], wherein the base substrate contains, as a main component, a crystal having a corundum structure in part or all of its surface.
[3] The method according to [1], wherein the base substrate contains, as a main component, a crystalline product having a β-gallia structure in part or all of the surface thereof.
[4] The method according to [3], wherein the crystalline product having the β-gallia structure is β-Ga ₂ O ₃ .
[5] A crystalline laminate structure obtained by using the manufacturing method according to any one of the above [1] to [4].
[6] A semiconductor device comprising the crystalline laminated structure according to the above [5].
[7] A semiconductor device including the crystalline laminated structure according to the above [5].
[8] A semiconductor device comprising at least the crystalline oxide thin film of the crystalline laminated structure according to the above [5] and an electrode.
[9] A crystalline oxide thin film containing a crystalline oxide having a β-gallia structure as a main component, directly or through another layer, on a base substrate,
A crystalline laminate structure characterized in that the crystalline oxide thin film contains germanium or silicon but does not substantially contain carbon and has a half width of 50 arcsec or less.

  In the crystalline laminated structure obtained by the manufacturing method of the present invention, the crystalline oxide thin film on the base substrate contains substantially no carbon, the half width is 50 arcsec or less, the half width is small, and the semiconductor characteristics Excellent.

The structural example of the crystalline laminated structure of one Embodiment of this invention is shown. It is a block diagram of the mist * epitaxy apparatus used in the Example of this invention. The AFM image in a present Example is shown.

  According to the manufacturing method of the present invention, the raw material fine particles generated by micronizing the raw material solution are supplied to the film forming chamber by the carrier gas, and the crystalline oxidation having the β-gallia structure on the base substrate disposed in the film forming chamber. Method of forming a crystalline laminated thin film containing a crystalline oxide thin film as a main component, wherein Ge or Si is used as a dopant to form a crystalline oxide thin film. It is characterized by doing. The crystalline layered structure of the present invention comprises a crystalline oxide thin film containing a crystalline oxide having a β-gallia structure as a main component, directly or through another layer, on a base substrate, The crystalline oxide thin film contains Ge or Si but contains substantially no carbon and has a half width of 50 arcsec or less.

  The “crystalline laminated structure” is a structure including one or more crystal layers, and may include a layer other than the crystal layer (eg, an amorphous layer). The crystalline layer is preferably a single crystal layer, but may be a polycrystalline layer. The crystalline oxide thin film is preferably a crystalline oxide semiconductor thin film, and the crystalline oxide semiconductor thin film may be after annealing treatment, whereby between the crystalline thin film and the ohmic electrode A metal oxide film in which an ohmic electrode is alloyed and mixed crystallized may be formed. Examples of the ohmic electrode include aluminum (Al), titanium (Ti), nickel (Ni), gold (Au), chromium (Cr), tungsten (W) and vanadium (V), and platinum (Pt). Examples include palladium (Pd), gold (Au) chromium (Cr), nickel (Ni), copper (Cu) and cobalt (Co).

  The crystalline oxide thin film contains Ge or Si. The content of Ge or Si in the composition of the crystalline oxide thin film is preferably 0.00001 at% or more, more preferably 0.00001 at% to 20 at%, 0.00001 Most preferably, it is atomic% to 10 atomic%.

  In addition, the crystalline oxide thin film contains substantially no carbon. Specifically, "substantially free of carbon" means that the content of carbon is 0.1 atomic% or less in the composition of the crystalline oxide thin film, and preferably 0. .01 atomic% or less, more preferably 0.001 atomic% or less.

  The crystalline oxide thin film has a half width of 50 arcsec or less. The half width is the half width of X-ray measurement (Out-of-plane measurement), and in the present invention, the half width of the crystalline oxide thin film is 40 arcsec or less. preferable.

<Base substrate>
The base substrate is not particularly limited as long as it can be a support of the above crystalline oxide thin film. It may be an insulator substrate, a semiconductor substrate, or a conductive substrate. In the present invention, the base substrate mainly comprises a substrate mainly comprising a crystal having a corundum structure in a part or all of the surface, or a crystal having a β-galia structure in a part or all of the surface It is preferable that it is a board | substrate containing as a component. The substrate containing as a main component a crystal having a corundum structure in a part or all of the surface is particularly preferably one containing 50% or more of a crystal having a corundum structure in the composition ratio of part or all of the substrate surface Although not limited, in the present invention, 70% or more is preferable, and 90% or more is more preferable. Examples of the substrate whose main component is a crystal having a corundum structure in part or all of the surface include, for example, a sapphire substrate (eg, c-plane sapphire substrate), an α-type gallium oxide substrate, and the like. A substrate mainly composed of a crystal having a β-gallia structure in a part or all of the surface is a substrate containing 50% or more of a crystal having a β-gallia structure in the composition ratio of a part or all of the substrate surface If it is included, it is not particularly limited, but in the present invention, the content is preferably 70% or more, and more preferably 90% or more. As a substrate containing as a main component a crystal having a β-gallia structure in part or all of the surface, for example, a β-Ga ₂ O ₃ substrate or a β-AlGaO based substrate (preferably Ga ₂ O ₃ and Al ₂ O _{3) 3} and a _Al 2 _{O 3} is mixed crystal substrate), and the like is often and 60 wt% or less than 0 wt%. Examples of other base substrates include substrates containing a crystal having a hexagonal crystal structure in part or all of the surface as a main component (example: SiC substrate, ZnO substrate, GaN substrate) and the like. Preferably, the crystalline oxide thin film is formed on the substrate having a hexagonal crystal structure directly or through another layer (eg, a buffer layer). The thickness of the base substrate is not particularly limited in the present invention, but is preferably 50 to 2000 μm, more preferably 200 to 800 μm.
In the present invention, the base substrate is a β-Ga ₂ O ₃ substrate or a mixed crystal substrate containing Ga ₂ O ₃ and Al ₂ O ₃ and having Al ₂ O ₃ in an amount of more than 0 wt% and 60 wt% or less. Is preferred, and a β-Ga ₂ O ₃ substrate is more preferred. By using such a preferable base substrate, the carbon content, carrier concentration and half width of the impurity of the crystalline oxide thin film can be further reduced as compared with the case where other base substrate is used.

<Crystalline oxide thin film>
The crystalline oxide thin film may contain crystalline oxide having a β-gallia structure as a main component, but it is preferable that the crystalline oxide is β-Ga ₂ O ₃ . When the crystalline oxide having a β-gallia structure is β-Ga ₂ O ₃ , the “main component” means that the atomic ratio of gallium in the metal element of the thin film is 0.5 or more and β-Ga That is fine if ₂ O ₃ is included. In the present invention, the atomic ratio of gallium in the metal element in the thin film is preferably 0.7 or more, more preferably 0.8 or more. Further, the thickness of the crystalline oxide semiconductor thin film is not particularly limited, and may be 1 μm or less, or 1 μm or more. The crystalline oxide thin film is usually single crystal but may be polycrystalline.

  The crystalline oxide thin film may be formed directly on the base substrate, or may be formed through another layer. As another layer, a corundum structure crystal thin film of another composition, a crystal thin film other than the corundum structure, an amorphous thin film, etc. may be mentioned. The structure may be a single layer structure or a multilayer structure. In addition, two or more crystal phases may be mixed in the same layer. In the case of the multilayer structure, the crystalline oxide thin film is formed by, for example, laminating an insulating thin film and a conductive thin film, but the present invention is not limited to this. When the insulating thin film and the conductive thin film are stacked to form a multi-layer structure, the compositions of the insulating thin film and the conductive thin film may be the same or may be different from each other. Although the ratio of the thickness of the insulating thin film to the thickness of the conductive thin film is not particularly limited, for example, the ratio of (the thickness of the conductive thin film) / (the thickness of the insulating thin film) is 0.001 to 100. Preferably, 0.1 to 5 is more preferable. More preferable ratios are specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, and the like. 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5 as exemplified herein It may be in the range between any two of the numerical values.

  The conductive thin film may be doped with an impurity to impart conductivity, as long as the object of the present invention is not impaired. The insulating thin film usually does not require doping with impurities, but may be doped to such an extent that conductivity does not appear.

  In the crystalline laminated structure of the present invention, the crystalline oxide is provided on the base substrate disposed in the film forming chamber by supplying the raw material fine particles generated by micronizing the raw material solution to the film forming chamber using the carrier gas. When forming a thin film, it manufactures by performing a doping process, using Ge or Si as a dopant. In the present invention, the doping treatment is preferably carried out by including the abnormal particle suppressor in the raw material solution. By carrying out the doping treatment by including the abnormal particle suppressor in the raw material solution, it is possible to efficiently and industrially advantageously manufacture a crystalline laminated structure provided with a crystalline oxide thin film having a surface roughness of 0.1 μm or less. Can. The doping amount of Ge or Si is not particularly limited as long as the object of the present invention is not impaired, but it is preferably 0.01 to 10% by volume ratio in the raw material solution, and 0.1 to 5%. Is more preferable.

  The abnormal particle suppressor refers to one that has the effect of suppressing the generation of particles by-produced in the film forming process, and is not particularly limited as long as the surface roughness of the crystalline oxide thin film can be 0.1 μm or less. In the present invention, it is preferable to be an abnormal particle suppressor comprising at least one selected from Br, I, F and Cl. When Br or I is introduced into the thin film as an abnormal grain suppressor to stably form a film, it is possible to suppress the deterioration of the surface roughness due to abnormal grain growth. The addition amount of the abnormal particle suppressor is not particularly limited as long as abnormal particles can be suppressed, but it is preferably 50% or less by volume ratio in the raw material solution, more preferably 30% or less, and 10 to 20% Most preferably, it is within the range. By using the abnormal particle suppressor in such a preferable range, it can be functioned as an abnormal particle inhibitor, so that the growth of abnormal particles of the crystalline oxide thin film can be suppressed to make the surface smooth. .

  The method for forming the crystalline oxide semiconductor thin film is not particularly limited as long as the object of the present invention is not impaired. For example, a gallium compound and optionally an indium compound, an aluminum compound or an iron compound may be combined with the composition of the crystalline oxide thin film It can be formed by subjecting the combined starting compounds to an oxidation reaction. Thus, the crystalline oxide semiconductor thin film can be crystal-grown on the base substrate from the base substrate side. As a gallium compound, it may be changed to a gallium compound immediately before film formation using gallium metal as a starting material. Examples of the gallium compound include organic metal complexes of gallium (eg, acetylacetonate complex) and halides (fluorination, chloride, bromide, or iodide). In the present invention, halides (fluoride) are used. It is preferred to use chloride, bromide or iodide).

  Although the film-forming temperature of a crystalline oxide semiconductor thin film is not specifically limited, 800 degrees C or less is preferable, and 700 degrees C or less is more preferable. The film formation may be performed under any atmosphere of vacuum, non-oxygen atmosphere, reducing gas atmosphere and oxygen atmosphere, as long as the object of the present invention is not impaired. It may be performed under any pressure, under pressure and under reduced pressure, but in the present invention, it is preferably performed under normal pressure or atmospheric pressure. Note that the film thickness can be set by adjusting the film formation time.

  The type of carrier gas is not particularly limited as long as the object of the present invention is not impaired. For example, oxygen, ozone, inert gas such as nitrogen or argon, or reducing gas such as hydrogen gas or forming gas is preferable. As an example. In addition, although one kind of carrier gas may be used, it may be two or more kinds, and a dilution gas (for example, 10-fold dilution gas etc.) in which the carrier gas concentration is changed may be used as the second carrier gas. You may use further. Further, the carrier gas may be supplied not only to one place, but also to two or more places. The flow rate of the carrier gas is not particularly limited, but is preferably 0.01 to 20 L / min, and more preferably 1 to 10 L / min.

  More specifically, in the crystalline oxide thin film, mist-like raw material fine particles generated from the raw material solution in which the raw material compound is dissolved are supplied to the film forming chamber to react the raw material compound in the film forming chamber. Can be formed by The solvent of the raw material solution is not particularly limited, but is preferably water, hydrogen peroxide water or an organic solvent. In the present invention, the above-mentioned starting compound is usually oxidized in the presence of a dopant starting material. The dopant raw material is preferably included in the raw material solution and is micronized together with the raw material compound.

  As a dopant raw material, the metal single-piece | unit or compound (example: halide, oxide) of Ge or Si to be doped etc. are mentioned.

  In the present invention, annealing may be performed after film formation. The temperature of the annealing treatment is not particularly limited, but is preferably 600 ° C. or more. By performing the annealing treatment at such a preferable temperature, the carrier concentration of the crystalline oxide semiconductor thin film can be more suitably reduced. The treatment time of the annealing treatment is not particularly limited as long as the object of the present invention is not impaired, but it is preferably 10 seconds to 10 hours, and more preferably 10 seconds to 1 hour.

  The crystalline oxide thin film of the crystalline laminate structure of the present invention obtained as described above has a half width of about 50 arcsec or less, preferably about 40 arcsec or less. The band gap is preferably 4.8 to 4.9 eV.

  In the present invention, an oxide semiconductor layer or / and a nitride semiconductor layer (for example, a GaN-based semiconductor layer or the like) may be provided on the crystalline oxide thin film directly or through another layer. .

<Configuration Example of Crystalline Laminated Structure>
A preferred example of the crystalline layered structure of the present embodiment and a semiconductor device using the same is shown in FIG. In the example of FIG. 1, the crystalline oxide thin film 3 is formed on the base substrate 1. The crystalline oxide semiconductor thin film 3 is configured by laminating the insulating thin film 3 a and the conductive thin film 3 b sequentially from the base substrate 1 side. The gate insulating film 5 is formed on the conductive thin film 3b. A gate electrode 7 is formed on the gate insulating film 5. Further, source / drain electrodes 9 are formed on the conductive thin film 3 b so as to sandwich the gate electrode 7. According to such a configuration, control of the depletion layer formed in the conductive thin film 3b can be performed by the gate voltage applied to the gate electrode 7, and transistor operation (FET device) becomes possible.

As a semiconductor device formed using the crystalline layered structure of the present embodiment, a transistor such as MIS or HEMT, a TFT, a Schottky barrier diode using a semiconductor-metal junction, PN combined with another P layer, or Examples include PIN diodes and light emitting and receiving elements. In the present invention, a Schottky electrode is provided directly or through another layer on the crystalline oxide thin film of the crystalline laminated structure, and the Schottky electrode is directly or separately formed on the base substrate of the crystalline laminated structure. A semiconductor device provided with an ohmic electrode is preferable via the layer of (4), and the semiconductor characteristics of the crystalline laminated structure can improve the reliability of the semiconductor device itself. Such novel and useful preferred semiconductor devices are also included in the semiconductor device of the present invention.
The Schottky electrode and the ohmic electrode may be known ones, and they may be provided to the crystalline laminated structure using known means. In addition, as another layer in the case of passing through another layer, a well-known semiconductor layer, an insulator layer, a conductor layer, etc. may be mentioned, and these layers may be known ones, and in the present invention, they are known. These layers can be stacked by means of

  Examples of the present invention will be described below, but the present invention is not limited thereto.

1. Mist-epitaxy device First, the mist-epitaxy device 19 used in the present embodiment will be described with reference to FIG. The mist / epitaxy apparatus 19 adjusts the flow rate of the carrier gas delivered from the sample stage 21 on which the film formation sample 20 such as the base substrate is placed, the carrier gas source 22 for supplying the carrier gas, and the carrier gas source 22. Flow control valve 23, mist generation source 24 containing raw material solution 24a, container 25 containing water 25a, ultrasonic transducer 26 attached to the bottom of container 25, quartz tube with an inner diameter of 40 mm And a heater 28 installed at the periphery of the film forming chamber 27. The sample table 21 is made of quartz, and the surface on which the film-forming sample 20 is placed is inclined from the horizontal surface. By forming both the film forming chamber 27 and the sample table 21 with quartz, it is possible to suppress the mixing of impurities derived from the device into the thin film formed on the film forming sample 20.

2. Preparation of Raw Material Solution <Example 1>
The aqueous solution is prepared by mixing gallium bromide and germanium oxide such that the concentration of gallium bromide is 0.1 mol / L and the atomic ratio of germanium is 0.04%. In a volume ratio of 10% and used as a raw material solution.

Example 2
The aqueous solution was prepared by mixing gallium bromide and germanium oxide such that the concentration of gallium bromide was 0.1 mol / L and the atomic ratio of germanium was 0.04%, and this was used as a raw material solution.

Example 3
The aqueous solution is prepared by mixing gallium bromide and germanium oxide such that the concentration of gallium bromide is 0.1 mol / L and the atomic ratio of germanium is 1%. It was made to contain so that it might be set to 10% in ratio, and this was made into the raw material solution.

Example 4
The aqueous solution is prepared by mixing gallium bromide and silicon oxide so that the concentration of gallium bromide is 0.1 mol / L and the atomic ratio of silicon is 0.04%. In a volume ratio of 10% and used as a raw material solution.

Example 5
The aqueous solution was prepared by mixing gallium bromide and silicon oxide so that the concentration of gallium bromide was 0.1 mol / L and the atomic ratio of silicon was 0.04%, and this was used as a raw material solution.

Example 6
The aqueous solution is prepared by mixing gallium bromide and silicon oxide so that the concentration of gallium bromide is 0.1 mol / L and the atomic ratio of silicon is 1%. It was made to contain so that it might be set to 10% in ratio, and this was made into the raw material solution.

Comparative Example 1
Only an aqueous solution of gallium acetylacetonate 0.1 mol / L was used as a raw material solution.

Comparative Example 2
An aqueous solution was prepared by mixing gallium acetylacetonate and tin oxide so that the concentration of gallium acetylacetonate was 0.1 mol / L and the atomic ratio of tin was 0.04%, and this was used as a raw material solution.

Comparative Example 3
An aqueous solution was prepared by mixing gallium acetylacetonate and titanium oxide so that the concentration of gallium acetylacetonate was 0.1 mol / L and the atomic ratio of titanium was 0.04%, and this was used as a raw material solution.

Comparative Example 4
An aqueous solution was prepared by mixing gallium acetylacetonate and tin oxide so that the concentration of gallium acetylacetonate was 0.1 mol / L and the atomic ratio of tin was 1%, and this was used as a raw material solution.

3. Preparation for film formation The raw material solution 24 a obtained in the above was contained in the mist generation source 24. Next, a square substrate (600 μm in thickness) with a side of 10 mm is placed on the sample table 21 as the film-forming sample 20, and the heater 28 is operated to raise the temperature in the film forming chamber 27 to 650 ° C. The temperature was raised. Next, the flow rate control valve 23 is opened to supply the carrier gas from the carrier gas source 22 into the film forming chamber 27 and the atmosphere in the film forming chamber 27 is sufficiently replaced with the carrier gas. Adjusted to min. Note that oxygen was used as a carrier gas, and in the examples, a β-Ga ₂ O ₃ substrate was used as the substrate. In the comparative example, a YSZ substrate was used.

4. Next, the ultrasonic transducer 26 was vibrated at 2.4 MHz, and the vibration was propagated through the water 25 a to the raw material solution 24 a to form the raw material solution 24 a into fine particles to generate raw material fine particles. The raw material fine particles are introduced into the film forming chamber 27 by the carrier gas, react in the film forming chamber 27, and a thin film is formed on the film forming sample 20 by a thermal reaction on the film forming surface of the film forming sample 20. It formed. The film thickness was controlled by adjusting the film formation time.

5. Evaluation Above 4. The phase of the β-Ga ₂ O ₃ thin film obtained in the above was identified. Identification was performed by performing 2θ / ω scanning at an angle of 15 ° to 95 ° using an XRD diffractometer for thin film. The measurement was performed using a CuK alpha ray.
Moreover, the presence and the half width of the obtained β-Ga ₂ O ₃ thin film of carbon impurities were measured. The carbon impurities were measured using a SIMS analyzer. The half width was measured using an X-ray analyzer.

  As described above, in each of the examples, the C content was less than the measurement limit, and both half widths were as low as 50 arcsec or less.

  In addition, with respect to the crystalline laminated structure of Example 1, the surface of the crystalline oxide thin film was observed by AFM. An AFM image is shown in FIG. It can be seen from FIG. 3 that the surface morphology is good.

  The crystalline layered structure of the present invention can be used in all fields such as semiconductors (for example, compound semiconductor electronic devices etc.), electronic parts / electrical equipment parts, optical / electrophotographic related apparatuses, industrial members, etc. In particular, semiconductor apparatuses Useful for

DESCRIPTION OF SYMBOLS 1 base substrate 3 crystalline oxide thin film 3a insulating thin film 3b conductive thin film 5 gate insulating film 7 gate electrode 9 source * drain electrode 19 mist * epitaxy apparatus 20 film-forming sample 21 sample stand 22 carrier gas source 23 flow control valve 24 mist generation source 24a raw material solution 25 container 25a water 26 ultrasonic transducer 27 film forming chamber 28 heater

Claims (3)

Raw material fine particles generated by micronizing a raw material solution containing a gallium compound are supplied to a film forming chamber by a carrier gas, and a crystalline oxide having a β-gallia structure is formed on a base substrate disposed in the film forming chamber. A method for producing a crystalline multilayer structure, comprising forming a crystalline oxide thin film containing as a main component, wherein the gallium compound does not contain carbon, and when forming the crystalline oxide thin film, the dopant is Ge or Si. Wherein the crystalline oxide thin film contains germanium or silicon, and a doping process is performed.   The method according to claim 1, wherein the base substrate contains, as a main component, a crystal having a β-galia structure in part or all of the surface thereof. The method according to claim ₂ , wherein the crystalline product having a β-gallia structure is β-Ga ₂ O ₃ .