JP2024040219A - Method for manufacturing gallium oxide semiconductor film and gallium oxide semiconductor film - Google Patents

Abstract

An object of the present invention is to provide a method for manufacturing a gallium oxide semiconductor film using a mist CVD method, which allows a high-quality gallium oxide semiconductor film with excellent crystallinity etc. to be obtained with high productivity. [Solution] A mist generated by atomizing or dropletizing a raw material solution is transported using a carrier gas, the mist is heated, and a film is formed by thermally reacting the mist on a substrate. A method for producing a gallium oxide semiconductor film, wherein the hydrogen ion concentration in the raw material solution is 1 x 10-12 to 1 x 10-2 mol/L. [Selection diagram] Figure 1

Description

The present invention relates to a method for manufacturing a gallium oxide semiconductor film, in which a gallium oxide semiconductor film is formed on a substrate using a mist-like raw material.

Conventionally, high-vacuum film-forming equipment that can realize non-equilibrium conditions has been developed, such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), and sputtering. It has become possible to manufacture oxide semiconductors, which were impossible to manufacture using methods such as the melt method. In addition, a mist chemical vapor deposition method (hereinafter also referred to as "mist CVD method") has been developed in which crystals are grown on a substrate using an atomized mist-like raw material. Ta. Unlike other CVD methods, the mist CVD method does not require high temperatures, and can also produce a metastable phase crystal structure such as the corundum structure of α-Ga ₂ O ₃ . As a semiconductor with a large band gap, α-Ga ₂ O ₃ is expected to be applied to next-generation switching elements that can realize high breakdown voltage, low loss, and high heat resistance.

Regarding the mist CVD method, Patent Document 1 describes a tube furnace type mist CVD apparatus. Patent Document 2 describes a fine channel type mist CVD apparatus. Patent Document 3 describes a linear source type mist CVD apparatus. Patent Document 4 describes a tube furnace mist CVD apparatus, which differs from the mist CVD apparatus described in Patent Document 1 in that a carrier gas is introduced into a mist generator. Patent Document 5 describes a mist CVD apparatus that is a rotating stage in which a base is installed above a mist generator and a susceptor is installed on a hot plate.

Japanese Patent Application Publication No. 1-257337 JP2005-307238A Japanese Patent Application Publication No. 2012-46772 Patent No. 5397794 JP2014-63973A

In the production of gallium oxide, it is customary to make the raw material solution strongly acidic with a pH of about 1 because it is necessary to dissolve gallium in the raw material solution. For example, when gallium bromide, gallium iodide, etc. are dissolved in water, the solution becomes acidic because the halide ions are ionized. Gallium acetylacetonate does not dissolve in water as it is, so it is mixed with an acid to promote dissolution. Furthermore, an aqueous solution in which metallic gallium is dissolved in hydrochloric acid or the like also becomes strongly acidic.

Upon investigation, the present inventors found that when a film is formed by mist CVD using a strong acidic solution as a raw material solution, a considerable amount of the metal members constituting the film forming apparatus are dissolved. As a result, it was found that the eluted metal was incorporated into the formed gallium oxide film, becoming crystal defects and recombination centers, and causing a decline in film quality. Furthermore, it was found that not only the film forming apparatus but also the accompanying equipment corroded, making maintenance of the apparatus necessary, leading to an increase in downtime, that is, a decrease in productivity.

An object of the present invention is to provide a method for manufacturing a gallium oxide semiconductor film using a mist CVD method, which allows a high-quality gallium oxide semiconductor film with excellent crystallinity etc. to be obtained with high productivity.

The present invention has been made to achieve the above-mentioned object, and the mist generated by atomizing or dropletizing a raw material solution is transported using a carrier gas, the mist is heated, and the mist is transferred onto a substrate. A method for producing a gallium oxide semiconductor film in which the mist is subjected to a thermal reaction to form a film, the method comprising oxidizing the hydrogen ion concentration in the raw material solution to 1×10 ⁻¹² to 1×10 ⁻² mol/L. A method for manufacturing a gallium semiconductor film is provided.

According to such a method for producing a gallium oxide semiconductor film, corrosion of the main body of the film forming apparatus is suppressed, metal contamination of the gallium oxide semiconductor film due to elution of metal members is suppressed, and a gallium oxide semiconductor film with good film quality can be produced. Can be manufactured efficiently. In addition, downtime of the film forming apparatus and ancillary equipment due to maintenance etc. is reduced, and productivity is improved. Furthermore, the members of the film forming apparatus, which were previously made of non-metallic materials to prevent corrosion, can now be made of metal, increasing the degree of freedom in designing the apparatus.

At this time, the hydrogen ion concentration in the raw material solution can be set to 3×10 ⁻¹¹ to 3×10 ⁻³ mol/L.

Thereby, corrosion of the film forming apparatus can be more effectively suppressed, downtime can be reduced, and a gallium oxide semiconductor film can be manufactured more efficiently.

At this time, the hydrogen ion concentration in the raw material solution can be set to 1×10 ⁻⁶ to 1×10 ⁻³ mol/L.

As a result, in addition to reducing metal contamination, it is also possible to increase the deposition rate of the gallium oxide semiconductor film.

At this time, the hydrogen ion concentration can be controlled by adjusting the amount of acid and/or base in the raw material solution.

Thereby, the hydrogen ion concentration in the raw material solution can be easily controlled.

At this time, ammonia can be used as the base.

Thereby, a high-quality gallium oxide semiconductor film with higher purity can be manufactured.

At this time, the substrate may be plate-shaped and have a surface area on which a film is formed of 100 mm ² or more.

Thereby, a gallium oxide semiconductor film with a large area and good film quality can be efficiently manufactured.

As described above, according to the method for manufacturing a gallium oxide semiconductor film according to the present invention, corrosion of a film forming apparatus can be suppressed. This not only suppresses metal contamination of the gallium oxide film due to elution of metal members and improves crystallinity, but also reduces downtime of the film forming apparatus and ancillary equipment due to maintenance, etc., and improves productivity. Furthermore, it is now possible to use metal for members that were previously made of non-metallic materials to prevent corrosion, increasing the degree of freedom in device design. Furthermore, it is also possible to improve the film formation rate.

1 is a schematic configuration diagram showing an example of a film forming apparatus that can be used in a method for manufacturing a gallium oxide semiconductor film according to the present invention. It is a figure explaining an example of a misting part. The evaluation results of the full width at half maximum of the gallium oxide semiconductor films manufactured in Examples and Comparative Examples are shown. The film-forming rates of gallium oxide semiconductor films in Examples and Comparative Examples are shown.

Hereinafter, the present invention will be explained in detail, but the present invention is not limited thereto.

As described above, there has been a need for a method for producing gallium oxide using a mist CVD method that can produce a high-quality gallium oxide semiconductor film with excellent crystallinity and the like with high productivity.

As a result of extensive studies on the above-mentioned issues, the present inventors have discovered that a mist generated by atomizing or dropletizing a raw material solution is transported using a carrier gas, heated, and then deposited on a substrate. A method for producing a gallium oxide semiconductor film in which the mist is subjected to a thermal reaction to form a film, the gallium oxide semiconductor film having a hydrogen ion concentration in the raw material solution of 1×10 ⁻¹² to 1×10 ⁻² mol/L. The present invention has been completed based on the discovery that a method for manufacturing a semiconductor film can efficiently manufacture a gallium oxide semiconductor film with better film quality, improve productivity, and further increase the degree of freedom in device design.

This will be explained below with reference to the drawings.

Here, the term "mist" as used in the present invention refers to a general term for fine liquid particles dispersed in gas, and includes what are called mist, droplets, and the like. Further, regarding the numerical range, for example, when it is written as "3 to 6", it means "3 or more and 6 or less".

(Film forming equipment)
FIG. 1 shows an example of a film forming apparatus 101 that can be used in the method for manufacturing a gallium oxide semiconductor film according to the present invention. The film forming apparatus 101 includes a misting section 120 that turns a raw material solution into a mist to generate mist, a carrier gas supply section 130 that supplies a carrier gas for transporting the mist, and heat-treats the mist to form a film on a substrate. It has a film forming section 140 and a transport section 109 that connects the mist forming section 120 and the film forming section 140 and transports the mist by a carrier gas. Further, the operation of the film forming apparatus 101 may be controlled by including a control unit (not shown) that controls the whole or a part of the film forming apparatus 101.

(Raw material solution)
The gallium oxide semiconductor film according to the present invention can further contain a metal other than gallium. Therefore, the raw material solution 104a is not particularly limited as long as it contains at least gallium and can be made into a mist. That is, in addition to gallium, it may contain one or more metals selected from, for example, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, iridium, nickel, and cobalt.

The raw material solution 104a is not particularly limited as long as it can turn the material containing the metal into a mist, but the raw material solution 104a may be one in which the metal is dissolved or dispersed in water in the form of a complex or salt. Can be used. Examples of the form of the complex include an acetylacetonate complex, a carbonyl complex, an ammine complex, and a hydride complex. Examples of the salt form include metal chloride, metal bromide, and metal iodide. Further, a solution of the above-mentioned metal in hydrobromic acid, hydrochloric acid, hydroiodic acid, etc. can also be used as an aqueous salt solution.

Further, the raw material solution may contain a dopant. The dopant is not particularly limited. Examples include n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium, or niobium, and p-type dopants such as copper, silver, tin, iridium, and rhodium. The concentration of the dopant may be, for example, from about 1×10 ¹⁶ /cm ³ to 1×10 ²² /cm ³ , and even at a low concentration of about 1×10 ¹⁷ /cm ³ or less, about 1×10 ²⁰ The concentration may be as high as /cm ³ or more.

Furthermore, an acid may be mixed in the raw material solution 104a to dissolve the raw material. Examples of the acid include hydrogen halides such as hydrobromic acid, hydrochloric acid, and hydroiodic acid, hypochlorous acid, chlorous acid, hypobromous acid, bromous acid, hypoiodic acid, and iodic acid. Examples include halogen oxoacids, formic acid, nitric acid, and the like.

Further, the hydrogen ion concentration (pH) can be adjusted by mixing a base into the raw material solution 104a. In this way, the hydrogen ion concentration in the raw material solution can be easily controlled. Examples of the base include potassium hydroxide, sodium hydroxide, ammonia, calcium hydroxide, barium hydroxide, magnesium hydroxide, copper hydroxide, iron hydroxide, and the like. Among these, ammonia is most preferred since it has a low boiling point and leaves no residue when the solution is heated.

In the method for manufacturing a gallium oxide semiconductor film according to the present invention, the hydrogen ion concentration in the raw material solution 104a needs to be 1×10 ⁻¹² to 1×10 ⁻² mol/L. The hydrogen ion concentration in the raw material solution 104a can be controlled by adjusting the amount of acid and/or base in the raw material solution 104a. By setting the hydrogen ion concentration to 1×10 ⁻² mol/L or less (pH≧2), corrosion of the film forming equipment and elution of equipment constituent members can be suppressed, and impurity contamination into the film can be suppressed. , a gallium oxide semiconductor film with good film quality can be efficiently manufactured. Further, by setting the hydrogen ion concentration to 1×10 ⁻¹² or more (pH≦12), a gallium oxide semiconductor film with good film quality can be efficiently and stably formed.

Further, it is preferable that the hydrogen ion concentration in the raw material solution 104a is 3×10 ⁻¹¹ to 3×10 ⁻³ mol/L. With such a hydrogen ion concentration range, corrosion of the device is more reliably suppressed, downtime is reduced, and a higher quality gallium oxide semiconductor film can be efficiently produced. Further, it is preferable that the hydrogen ion concentration in the raw material solution 104a is 1×10 ⁻⁶ to 1×10 ⁻³ mol/L. Within this range, in addition to the above effects, it is possible to improve the film formation rate.

(Misting department)
In the misting section 120, the raw material solution 104a is adjusted and the raw material solution 104a is made into a mist to generate mist. The misting means is not particularly limited as long as it can make the raw material solution 104a into a mist, and may be any known misting means, but it is preferable to use a misting means using ultrasonic vibration. This is because mist can be formed more stably.

An example of such a misting section 120 is shown in FIG. For example, it may include a mist generation source 104 containing a raw material solution 104a, a container 105 containing a medium capable of transmitting ultrasonic vibrations, such as water 105a, and an ultrasonic vibrator 106 attached to the bottom of the container 105. good. Specifically, a mist generation source 104 made of a container containing a raw material solution 104a is housed in a container 105 containing water 105a using a support (not shown). An ultrasonic transducer 106 is provided at the bottom of the container 105, and the ultrasonic transducer 106 and an oscillator 116 are connected. When the oscillator 116 is activated, the ultrasonic vibrator 106 vibrates, and the ultrasonic wave propagates into the mist generation source 104 through the water 105a, so that the raw material solution 104a becomes a mist.

(Transportation section)
The transport section 109 connects the misting section 120 and the film forming section 140. The mist is transported by carrier gas from the mist generation source 104 of the mist forming section 120 to the film forming chamber 107 of the film forming section 140 via the transport section 109 . The conveyance section 109 can be, for example, a supply pipe 109a. As the supply pipe 109a, for example, a quartz tube or a resin tube can be used.

(Film forming section)
In the film forming section 140, the mist is heated to cause a thermal reaction to form a film on part or all of the surface of the base 110. The film forming unit 140 includes, for example, a film forming chamber 107, a base 110 is installed in the film forming chamber 107, and a heating means for heating the base 110, for example, a hot plate 108. . The hot plate 108 may be provided outside the film forming chamber 107 as shown in FIG. 1, or may be provided inside the film forming chamber 107. In addition to using a hot plate, heating can also be performed using light or the like that can be absorbed by the base and generate heat. Further, the film forming chamber 107 may be provided with an exhaust gas exhaust port 112 at a position that does not affect the supply of mist to the substrate 110. Note that the base body 110 may be placed on the top surface of the film forming chamber 107 so as to be placed face down, or the base body 110 may be placed on the bottom surface of the film forming chamber 107 and may be placed face up.

(Base)
The base 110 is not particularly limited as long as it can form a film and support a film. The material of the base 110 is not particularly limited, and any known base may be used, and may be an organic compound or an inorganic compound. For example, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluorine resin, iron, aluminum, stainless steel, metals such as gold, silicon, sapphire, quartz, glass, gallium oxide, etc. These include, but are not limited to. The shape of the substrate may be any shape, and is effective for all shapes, such as plate shapes such as flat plates and disks, fiber shapes, rod shapes, cylinder shapes, prismatic shapes, Examples include cylindrical, spiral, spherical, and ring shapes, but in the present invention, it is preferable to use a plate-shaped substrate. The thickness of the plate-like substrate is not particularly limited, but is preferably 10 to 2000 μm, more preferably 50 to 800 μm. When the base is plate-shaped, its area is preferably 100 mm ² or more, and more preferably the diameter is 2 inches (50 mm) or more.

(Carrier gas supply section)
The carrier gas supply unit 130 has a carrier gas source 102a that supplies carrier gas, and has a flow rate control valve for adjusting the flow rate of the carrier gas (sometimes referred to as "main carrier gas") sent out from the carrier gas source 102a. 103a. Further, a dilution carrier gas source 102b that supplies a dilution carrier gas as needed, and a flow rate adjustment valve 103b for adjusting the flow rate of the dilution carrier gas sent out from the dilution carrier gas source 102b can also be provided. .

The type of carrier gas is not particularly limited, and can be appropriately selected depending on the film to be formed. Examples include oxygen, ozone, inert gases such as nitrogen and argon, and reducing gases such as hydrogen gas and forming gas. Furthermore, the number of types of carrier gas may be one or two or more types. For example, a diluted gas obtained by diluting the same gas as the first carrier gas with another gas (for example, 10 times diluted) may be further used as the second carrier gas, or air may also be used. In this specification, simply "flow rate of carrier gas" means the total flow rate of carrier gas. For example, the total flow rate of the main carrier gas sent out from the carrier gas source 102a and the flow rate of the dilution carrier gas sent out from the dilution carrier gas source 102b is defined as the carrier gas flow rate. The flow rate of the carrier gas is appropriately determined depending on, for example, the size of the film forming chamber, the film forming temperature, the raw material solution, etc., and can be, for example, about 2 to 30 L/min.

(Production method)
Next, an example of a method for manufacturing a gallium oxide semiconductor film according to the present invention will be described below with reference to FIG.

First, a raw material solution 104a adjusted to a desired hydrogen ion concentration (pH) is contained in the mist generation source 104 of the misting section 120, and the substrate 110 is placed on the hot plate 108 directly or through the wall of the film forming chamber 107. and operate the hot plate 108.

Next, the flow rate control valves 103a and 103b are opened to supply carrier gas from the carrier gas sources 102a and 102b into the film forming chamber 107, and the atmosphere in the film forming chamber 107 is sufficiently replaced with the carrier gas, and the main carrier gas The flow rate of the carrier gas and the flow rate of the carrier gas for dilution are adjusted respectively to control the carrier gas flow rate.

Next, mist is generated. By vibrating the ultrasonic vibrator 106 and propagating the vibration to the raw material solution 104a through the water 105a in the container 105, the raw material solution 104a is turned into a mist to generate mist. Next, the mist generated in the mist forming section 120 is transported from the mist forming section 120 via the transport section 109 to the film forming section 140 by the carrier gas, and introduced into the film forming chamber 107 . The mist introduced into the film forming chamber 107 is heat-treated by the heat of the hot plate 108 in the film forming chamber 107 and undergoes a thermal reaction, thereby forming a film on the substrate 110 .

The thermal reaction only requires that the mist reacts by heating, and the reaction conditions are not particularly limited. It can be set appropriately depending on the raw material and the film to be formed. For example, the heating temperature can be in the range of 120 to 600°C, preferably in the range of 200 to 600°C, more preferably in the range of 300 to 550°C.

Further, the thermal reaction may be performed in any of a non-oxygen atmosphere, a reducing gas atmosphere, an air atmosphere, and an oxygen atmosphere, and may be appropriately set depending on the film to be formed. The reaction pressure may be atmospheric pressure, increased pressure, or reduced pressure; however, film formation under atmospheric pressure is preferable because the apparatus configuration can be simplified.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereto.

(Example 1)
Based on the above-described method for manufacturing a gallium oxide semiconductor film, a gallium oxide (α-Ga ₂ O ₃ ) film having a corundum structure was formed as an oxide semiconductor film containing gallium as a main component.

Specifically, first, an aqueous solution of 1×10 ^-1 mol/L of gallium chloride is prepared, and a potassium hydroxide (KOH) aqueous solution is added to this to adjust the hydrogen ion concentration (pH). The concentration was set to 1×10 ⁻² mol/L (pH=2), and this was used as the raw material solution 104a.

The raw material solution 104a obtained as described above was contained in the mist generation source 104. Next, a 4 inch (diameter 100 mm) c-plane sapphire substrate was placed as the base 110 in the film forming chamber 107 so as to be adjacent to the hot plate 108 . Then, the hot plate 108 was operated to raise the temperature to 500°C. Note that, due to the need to reduce temperature fluctuations during film formation, the material of the film formation chamber 107 was aluminum, which has good thermal conductivity.

Subsequently, the flow control valves 103a and 103b were opened to supply oxygen gas as a carrier gas into the film forming chamber 107 from the carrier gas sources 102a and 102b, and the atmosphere in the film forming chamber 107 was sufficiently replaced with the carrier gas. Thereafter, the flow rate of the main carrier gas was set to 8 L/min, and the flow rate of the diluting carrier gas was set to 18 L/min.

Next, the ultrasonic vibrator 106 was vibrated at 2.4 MHz, and the vibration was propagated to the raw material solution 104a through the water 105a in the container 105, thereby turning the raw material solution 104a into a mist. This mist was introduced into the film forming chamber 107 via the supply pipe 109a using a carrier gas. Then, the mist was subjected to a thermal reaction in the film forming chamber 107 at 500° C. under atmospheric pressure to form a thin film of α-Ga ₂ O ₃ on the substrate 110. The film forming time was 30 minutes.

The obtained sample was subjected to X-ray diffraction measurement to evaluate crystallinity. Specifically, the rocking curve of the (0006) plane diffraction peak of α-Ga ₂ O ₃ was measured, and its full width at half maximum was determined. Furthermore, the degree of contamination in the film was evaluated by energy dispersive X-ray analysis (EDS). In addition, the film thickness was measured using an interferometric film thickness meter. The film formation rate was determined by dividing the obtained film thickness by 0.5 hours (30 minutes) of the film formation time.

(Example 2)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁴ mol/L (pH=4), and film formation and evaluation were performed under the same conditions as in Example 1 except for this.

(Example 3)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁷ mol/L (pH=7), and film formation and evaluation were performed under the same conditions as in Example 1 except for this.

(Example 4)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁹ mol/L (pH=9), and film formation and evaluation were performed under the same conditions as in Example 1 except for this.

(Example 5)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻¹² mol/L (pH=12), and film formation and evaluation were performed under the same conditions as in Example 1 except for this.

(Example 6)
The film was formed under the same conditions as in Example 1, except that the hydrogen ion concentration (pH) was adjusted using ammonia water (NH ₃ (aq)) instead of the potassium hydroxide (KOH) aqueous solution in Example 1. , conducted an evaluation.

(Example 7)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁴ mol/L (pH=4), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Example 8)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁷ mol/L (pH=7), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Example 9)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁹ mol/L (pH=9), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Example 10)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻¹¹ mol/L (pH=11), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Example 11)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻³ mol/L (pH=3), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Example 12)
The hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻⁶ mol/L (pH=6), and film formation and evaluation were performed under the same conditions as in Example 6 except for this.

(Comparative example 1)
Hydrogen ion concentration (pH) was adjusted using a hydrogen bromide (HBr) aqueous solution instead of potassium hydroxide in Example 1, and the hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻¹ mol/L (pH= Film formation and evaluation were performed under the same conditions as in Example 1, except that the conditions were adjusted to satisfy 1).

(Comparative example 2)
In Example 1, film formation and evaluation were performed under the same conditions as in Example 1, except that the hydrogen ion concentration of the raw material solution 104a was adjusted to 1×10 ⁻¹³ mol/L (pH=13).

Table 1 shows the raw material solution conditions and evaluation results of Examples 1 to 12 and Comparative Examples 1 and 2. Further, FIG. 3 shows the evaluation results of the full width at half maximum of the gallium oxide semiconductor films manufactured in Examples and Comparative Examples, and FIG. 4 shows the deposition rates of the gallium oxide semiconductor films in Examples and Comparative Examples.

As is clear from Table 1, Examples 1 to 12 have smaller full widths at half maximum than Comparative Example 1, indicating that the α-Ga ₂ O ₃ films have excellent crystallinity. Furthermore, according to the EDS evaluation results, in Comparative Example 1, Al, which is considered to be derived from members constituting the manufacturing equipment, was detected, but in Examples 1 to 12, no elements other than Ga and O were detected, resulting in impurity contamination. was not recognized. This is because by lowering the hydrogen ion concentration in the raw material solution, elution of the manufacturing equipment components such as the film forming chamber is suppressed, preventing impurity contamination in the film, and as a result, crystallinity is also improved. It is thought that it was done. Furthermore, in Examples 1-12, an improvement in film formation rate was observed compared to the comparative example. In particular, in Examples 2, 7, 11, and 12 where the hydrogen ion concentration was 1×10 ⁻³ to 1×10 ⁻⁶ mol/L (pH=3 to 6), the film formation rate was significantly improved. .

Note that the present invention is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and any embodiment that has substantially the same configuration as the technical idea stated in the claims of the present invention and has similar effects is the present invention. covered within the technical scope of.

101... Film forming apparatus, 102a... Carrier gas source,
102b...Dilution carrier gas source, 103a...Flow rate control valve,
103b...flow control valve, 104...mist generation source, 104a...raw material solution,
105... Container, 105a... Water, 106... Ultrasonic vibrator, 107... Film forming chamber,
108... Hot plate, 109... Conveying section, 109a... Supply pipe,
110... Base, 112... Exhaust port, 116... Oscillator,
120... Mist forming section, 130... Carrier gas supply section, 140... Film forming section.

Claims (6)

A method for manufacturing a gallium oxide semiconductor film, the method comprising:
A method for producing a gallium oxide semiconductor film, comprising forming a gallium oxide semiconductor film in which metal elements other than Ga are not detected in energy dispersive X-ray analysis (EDS). 1. The crystallinity of the gallium oxide semiconductor film is improved by forming the gallium oxide semiconductor film in which metal elements other than Ga are not detected in the energy dispersive X-ray analysis (EDS). A method for producing a gallium oxide semiconductor film according to . A gallium oxide semiconductor film,
A gallium oxide semiconductor film characterized in that metal elements other than Ga are not detected in energy dispersive X-ray analysis (EDS). 4. The gallium oxide semiconductor film according to claim 3, wherein the full width at half maximum of a rocking curve of a (0006) plane diffraction peak measured by X-ray diffraction is 79 seconds or less. The gallium oxide semiconductor film according to claim 3 or 4, characterized in that the film thickness is 1.1 μm or more. The gallium oxide semiconductor film according to any one of claims 3 to 5, wherein the surface area of the film is 100 ^mm2 or more.

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