Film forming apparatus, film forming method, gallium oxide film and laminate

Abstract

The present invention is a film formation device which forms a film on a substrate through the heat treatment of a starting material solution in the form of a mist, the film formation device comprising a mist conversion unit that generates a mist by converting the starting material solution into mist, a carrier gas supply unit that supplies a carrier gas for transporting the mist generated by the mist conversion unit, a film formation unit that includes therein a placement part for placing the substrate and that is where the mist transported by the carrier gas is supplied onto the substrate, and an exhaust unit that exhausts exhaust gas from the film formation unit, and further comprising, above the placement part in the film formation unit, a nozzle for supplying the mist onto the substrate and a top plate for adjusting the flow of the mist supplied from the nozzle. The present invention thereby provides a film formation device and a film formation method in which mist CVD can be applied and with which a film having excellent in-plane uniformity of film thickness can be formed.

Description

[Technical Field]

[0001] The present invention relates to a film formation apparatus for forming a film on a substrate using a mist-like raw material solution, a film formation method, a gallium oxide film, and a laminate. [Background technology]

[0002] High-vacuum deposition equipment capable of realizing non-equilibrium conditions, such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), and sputtering, has been developed, enabling the fabrication of oxide semiconductors that were previously impossible using melt deposition and other methods. Furthermore, mist chemical vapor deposition (Mist CVD), which uses atomized raw materials to grow crystals on a substrate, has been developed, enabling the fabrication of corundum-structured gallium oxide (α-Ga2O3). As a wide-bandgap semiconductor, α-Ga2O3 is expected to be applied to next-generation switching devices, achieving high voltage resistance, low loss, and high heat resistance.

[0003] Regarding the mist CVD method, Patent Document 1 describes a tubular 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 tubular furnace mist CVD apparatus, which differs from the mist CVD apparatus described in Patent Document 1 in that a carrier gas is introduced into the mist generator. Patent Document 5 describes a mist CVD apparatus in which a substrate is placed above a mist generator and a susceptor is a rotating stage mounted on a hot plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-257337 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-307238 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-46772 [Patent Document 4] Patent No. 5397794 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-63973 Summary of the Invention [Problem to be solved by the invention]

[0005] Unlike other CVD methods, the mist CVD method allows for film formation at relatively low temperatures, and is also capable of producing metastable phase crystal structures such as the corundum structure of α-Ga2O3. However, the inventors discovered a problem in that when mist is supplied from above the substrate, the flow of the mist is disturbed by thermal convection and mixing of the gas containing the mist with the ambient gas, making it difficult to maintain uniformity in the thickness of the deposited film across the surface.

[0006] The present invention has been made to solve the above problems, and aims to provide a film formation apparatus and a film formation method to which the mist CVD method can be applied and which can form a film with excellent in-plane film thickness uniformity. [Means for solving the problem]

[0007] The present invention has been made to achieve the above object, and provides a film formation apparatus for forming a film on a substrate by heat-treating a mist of a raw material solution, the apparatus comprising: a mist generating unit that generates mist by misting the raw material solution; a carrier gas supply unit that supplies a carrier gas that carries the mist generated in the mist generating unit; a film forming unit including a mounting unit for mounting the substrate thereon, and the mist carried by the carrier gas is supplied onto the substrate; an exhaust unit that exhausts exhaust gas from the film forming unit; Equipped with Above the placement unit in the film forming unit, a nozzle for supplying the mist onto the substrate; A top plate that rectifies the mist supplied from the nozzle; The present invention provides a film forming apparatus further comprising:

[0008] This type of film deposition apparatus can deposit a film with excellent in-plane uniformity in thickness. The combined effect of the flow straightening effect of the top plate and the convection generated by the supply of mist from the nozzle and the exhaust of exhaust gas from the exhaust section creates a uniform gas flow above and along the substrate (parallel to the substrate surface), enabling the deposition of a uniform film on the substrate.

[0009] The nozzle and the top plate may be disposed vertically above the placement portion. This makes it possible to form a film with good in-plane uniformity in film thickness.

[0010] The top plate may be disposed in contact with a side surface of the nozzle. This makes it possible to form a film with good in-plane uniformity in film thickness.

[0011] The top plate may be disposed in the same plane as the opening surface of the nozzle. This makes it possible to form a film with good in-plane uniformity in film thickness.

[0012] The top plate may be installed so that the bottom surface of the top plate is parallel to the surface of the mounting section on which the substrate is mounted. This makes it possible to form a film with good in-plane uniformity in film thickness.

[0013] The top plate may be installed so that the difference in height between the bottom surface of the top plate and the surface of the mounting section on which the substrate is placed is 0.15 cm or more and 6.05 cm or less. This makes it possible to form a film with even better in-plane film thickness uniformity.

[0014] The nozzle may be installed so that the difference in height between the opening surface of the nozzle and the substrate placed on the placement section is 0.1 cm or more and 6.0 cm or less. This makes it possible to form a film with even better in-plane film thickness uniformity.

[0015] In addition, the area of ​​the bottom surface of the top plate is B [cm 2 ], B≧40 can be satisfied. This makes it possible to form a film with even better in-plane film thickness uniformity.

[0016] The area of ​​the substrate is defined as A [cm 2 ], the area of ​​the bottom surface of the top plate is B [cm 2 ], B / A≧0.5 can be satisfied. This makes it possible to form a film with even better in-plane film thickness uniformity.

[0017] The apparatus may further include a moving mechanism that moves the substrate below the nozzle. This makes it possible to form a film with good in-plane uniformity in film thickness over a large area.

[0018] The raw material solution may contain gallium. This makes it possible to form a gallium oxide film with good in-plane uniformity in film thickness.

[0019] The raw material solution may contain a halogen. This makes it possible to form a film with good in-plane uniformity in film thickness.

[0020] The present invention also provides a film formation method for forming a film on a substrate by heat-treating a mist of a raw material solution, the method comprising the steps of: a mist generating step of misting the raw material solution to generate mist; a mist transport step of transporting the mist to a film forming unit by a carrier gas; a film-forming step of supplying the mist onto the substrate placed on a placement unit in the film-forming unit to perform heat treatment and film formation while exhausting exhaust gas; Including, In the film forming step, The mist is supplied onto the substrate from a nozzle provided above the mounting portion between the substrate and a top plate provided above the mounting portion, thereby supplying the mist onto the substrate in a rectified state.

[0021] This allows deposition of a film with excellent in-plane uniformity in thickness. The combined effect of the rectifying effect of the top plate and the convection generated by the supply of mist from the nozzle and the exhaust of exhaust gas creates a uniform gas flow above and along the substrate (parallel to the substrate surface), enabling the deposition of a uniform film on the substrate.

[0022] The nozzle and the top plate can be installed vertically above the placement section. This allows deposition of a film with good in-plane uniformity in film thickness.

[0023] The top plate can be installed in contact with the side surface of the nozzle. This allows deposition of a film with good in-plane uniformity in film thickness.

[0024] The top plate can be installed in the same plane as the opening surface of the nozzle. This allows deposition of a film with good in-plane uniformity in film thickness.

[0025] The top plate can be installed so that the bottom surface of the top plate is parallel to the surface of the mounting section on which the substrate is mounted. This allows deposition of a film with good in-plane uniformity in film thickness.

[0026] The top plate can be installed so that the difference in height between the bottom surface of the top plate and the surface of the mounting section on which the substrate is placed is 0.15 cm to 6.05 cm. This allows the deposition of a film with even better in-plane film thickness uniformity.

[0027] The nozzle may be installed so that the difference in height between the opening surface of the nozzle and the substrate placed on the placement section is 0.1 cm to 6.0 cm. This allows the deposition of a film with even better in-plane film thickness uniformity.

[0028] In addition, the area of ​​the bottom surface of the top plate is B [cm 2 ], then B≧40 can be satisfied. This allows the deposition of a film with even better in-plane film thickness uniformity.

[0029] The area of ​​the substrate is defined as A [cm 2 ], the area of ​​the bottom surface of the top plate is B [cm 2 ], then B / A≧0.5 can be satisfied. This allows the deposition of a film with even better in-plane film thickness uniformity.

[0030] In addition, in the film forming step, the substrate can be moved below the nozzle. This allows a film with good in-plane uniformity in film thickness to be formed over a large area.

[0031] The raw material solution may also contain gallium. This allows the deposition of a gallium oxide film with excellent in-plane film thickness uniformity.

[0032] The raw material solution may contain a halogen. This allows deposition of a film with good in-plane uniformity in film thickness.

[0033] Furthermore, when the flow rate of the carrier gas supplied from the nozzle is Q [L / min] and the flow rate of the exhaust gas is E [L / min], E / Q can be set to 5 or less. This allows the deposition of a film with even better in-plane film thickness uniformity.

[0034] In addition, the substrate is formed on a substrate having an area of ​​50 cm 2 or greater than 4 inches (100 mm) in diameter. This allows a film with good in-plane uniformity in film thickness to be formed over a large area.

[0035] The present invention also provides a gallium oxide film having a corundum structure, The gallium oxide film has an area of ​​50 cm 2 or more, or a diameter of 4 inches (100 mm) or more, The gallium oxide film is characterized in that the in-plane distribution of the thickness of the gallium oxide film is between ±3.1% and ±11.7%.

[0036] Such a gallium oxide film is a large-area film with good in-plane uniformity of film thickness.

[0037] The present invention also provides a laminate of a gallium oxide film having a corundum structure and a substrate, The gallium oxide film of the laminate has an area of ​​50 cm 2 or more, or a diameter of 4 inches (100 mm) or more, The laminate is characterized in that the in-plane distribution of the thickness of the gallium oxide film is ±3.1% or more and 11.7% or less.

[0038] Such a laminate is a laminate having a large area of ​​gallium oxide film with good in-plane film thickness uniformity on a substrate. [Effects of the Invention]

[0039] As described above, the film formation apparatus and film formation method of the present invention make it possible to form a film with good in-plane uniformity of film thickness on a substrate using a mist-like raw material solution. Furthermore, with the gallium oxide film or laminate of the present invention, a large-area gallium oxide film with good in-plane uniformity of film thickness can be obtained. [Brief explanation of the drawings]

[0040] [Figure 1] 1 is a schematic diagram illustrating an example of a film forming apparatus according to the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of a mist generating unit according to the present invention. [Figure 3] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of a nozzle according to the present invention. [Figure 5] FIG. 10 is a diagram illustrating an example in which a plurality of nozzles are provided. [Figure 6] FIG. 10 is a diagram illustrating an example of a nozzle having a plurality of nozzle opening surfaces. [Figure 7] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 8] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 9] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 10] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 11] FIG. 2 is a diagram illustrating an example of a film forming unit in the present invention. [Figure 12] 1A to 1C are diagrams illustrating an example of a substrate moving mechanism in the present invention. [Figure 13] 10A and 10B are diagrams illustrating an example of a moving mechanism that reciprocates under the nozzle. [Figure 14] 10A and 10B are diagrams illustrating an example of a moving mechanism that rotates and moves the area below the nozzle in one direction. [Figure 15] FIG. 13 is a diagram showing the top plate used in Example 10. [Figure 16]FIG. 2 is a diagram illustrating an example of an exhaust unit in the present invention. [Figure 17] FIG. 2 is a diagram showing a top plate (rectangular shape) used in the examples. [Figure 18] FIG. 13 is a diagram illustrating an example of a film forming apparatus used in Example 13. [Figure 19] 1 is a schematic cross-sectional view showing an example of a gallium oxide film and a laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] The present invention will be described in detail below, but the present invention is not limited thereto. As described above, there has been a demand for a film formation apparatus and a film formation method that can form a film with good in-plane uniformity in film thickness in the mist CVD method. As a result of extensive research into the above-mentioned problems, the inventors have found that a film formation apparatus for forming a film on a substrate by heat-treating a mist of a raw material solution, the film formation apparatus comprising: a mist-forming unit that mists the raw material solution to generate the mist; a carrier gas supply unit that supplies a carrier gas that transports the mist generated in the mist-forming unit; a film formation unit that has an internal mounting unit for mounting the substrate and in which the mist transported by the carrier gas is supplied onto the substrate; and an exhaust unit that exhausts exhaust gas from the film formation unit; and further comprising, above the mounting unit within the film formation unit, a nozzle that supplies the mist onto the substrate, and a top plate that rectifies the mist supplied from the nozzle, which makes it possible to form a film with excellent in-plane uniformity in film thickness, and have completed the present invention.

[0042] The present inventors have also found that a film formation method for forming a film on a substrate by heat-treating a mist of raw material solution includes a mist generation step of misting the raw material solution to generate the mist, a mist transport step of transporting the mist to a film formation unit by a carrier gas, and a film formation step of supplying the mist onto the substrate placed on a mounting unit within the film formation unit, heat-treating the substrate and forming a film while exhausting exhaust gas, wherein the mist is supplied onto the substrate from a nozzle provided above the mounting unit between the substrate and a top plate provided above the mounting unit in the film formation step, thereby supplying the mist that has been rectified onto the substrate, thereby forming a film with excellent in-plane uniformity in film thickness, and have completed the present invention.

[0043] Also, a gallium oxide film having a corundum structure, the gallium oxide film having an area of ​​50 cm 2 a gallium oxide film having an area of ​​50 cm or more, or a diameter of 4 inches (100 mm) or more, and an in-plane distribution of the film thickness of the gallium oxide film being between ±3.1% and ±11.7%; and a laminate of a gallium oxide film having a corundum structure and a substrate, wherein the gallium oxide film of the laminate has an area of ​​50 cm or more, 2 The inventors have found that a large-area gallium oxide film with good in-plane uniformity in film thickness or a laminate having the gallium oxide film on a substrate can be obtained by using a laminate characterized by having a diameter of 4 inches (100 mm) or more, and an in-plane distribution of the film thickness of the gallium oxide film being between ±3.1% and ±11.7%, and have completed the present invention.

[0044] The following description will be made with reference to the drawings. (gallium oxide film) FIG. 19 shows a schematic cross-sectional view of an example of the gallium oxide film of the present invention (and the laminate of the present invention). The gallium oxide film 180 having a corundum structure according to the present invention has an area of ​​50 cm 2The film thickness is characterized by a thickness of 4 inches (100 mm) or more, or a diameter of 4 inches (100 mm) or more, and an in-plane distribution of the film thickness of ±3.1% to 11.7%. The larger the film area and diameter, the larger the film area that can be obtained, so there is no particular upper limit. However, an example of the upper limit is an area of ​​750 cm. 2 Alternatively, the diameter can be 12 inches (300 mm). Generally, oxide semiconductor films are composed of metal and oxygen, but in the gallium oxide film 180 according to the present invention, the metal is mainly composed of gallium. Here, "mainly composed" means that 50 to 100% of the metal components is gallium. As the metal component other than gallium, for example, one or more metals selected from iron, indium, aluminum, vanadium, titanium, chromium, rhodium, iridium, nickel, and cobalt may be included.

[0045] The in-plane distribution of the film thickness is between ±3.1% and ±11.7%, and more preferably less than ±8.2%. Here, the in-plane distribution of the film thickness in the present invention is, for example, measured at nine or more points in the plane, Film thickness distribution [±%] = (maximum film thickness - minimum film thickness) / (average film thickness) / 2 x 100 The film thickness can be measured using a step-type film thickness meter (step gauge), an optical interference film thickness meter, or the like, but the measurement method is not particularly limited as long as it can measure the film thickness at each location.

[0046] The reasons why the in-plane distribution of film thickness deteriorates (increases) in conventional film formation devices and methods are thought to be non-uniformity in the amount of mist supplied due to the mist supply method, supply amount, structure around the substrate, etc., and temperature distribution on the substrate, etc. Therefore, the inventors conducted extensive research and, as a result of repeated trial and error, came to the conclusion that by optimizing the structure around the substrate, as in the film formation device described below, the supply amount can be made uniform and the in-plane uniformity of the film thickness distribution can be improved, and for the first time, they succeeded in obtaining a large-area film with good uniformity in the in-plane distribution of film thickness as described above.

[0047] Furthermore, the gallium oxide film 180 according to the present invention can contain a dopant depending on the application. The dopant is not particularly limited. Examples include n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium, and niobium, and p-type dopants such as copper, silver, tin, iridium, and rhodium. The dopant concentration is, for example, about 1.0×10 16 ~1.0×10 22 / cm 3 may be about 1.0 x 10 17 / cm 3 Even at low concentrations below 1.0 × 10 20 / cm 3 A concentration higher than this may be used.

[0048] There is no particular limitation on the film thickness of the oxide semiconductor film 180 according to the present invention. For example, it may be 0.05 to 100 μm, preferably 0.1 to 50 μm, and more preferably 0.5 to 20 μm.

[0049] (Laminate) The laminate 181 according to the present invention is formed on the substrate 110 with an area of ​​50 cm 2 The device is characterized by having a gallium oxide film 180 having a corundum structure and a diameter of 4 inches (100 mm) or more.

[0050] Another layer may be interposed between the substrate 110 and the gallium oxide film 180. The other layer is a layer having a different composition from the substrate 110 and the outermost gallium oxide film 180, and may be, for example, a crystalline oxide film, an insulating film, a metal film, or the like.

[0051] The gallium oxide film 180 and stacked body 181 according to the present invention can be used in semiconductor devices by appropriately designing the structure thereof, such as forming semiconductor layers in Schottky barrier diodes (SBDs), metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), metal oxide semiconductor field effect transistors (MOSFETs), static induction transistors (SITs), junction field effect transistors (JFETs), insulated gate bipolar transistors (IGBTs), and light emitting diodes (LEDs).

[0052] The gallium oxide film 180 and the laminate 181 according to the present invention can be obtained by performing film formation using a film formation apparatus according to the present invention, which will be described later. The film formation apparatus and film formation method according to the present invention will now be described. Here, the term "mist" as used in the present invention refers to a general term for fine particles of liquid dispersed in a gas, and includes what is called fog, droplets, and the like.

[0053] (Film forming equipment) 1 shows an example of a film formation apparatus 101 of the present invention. The film formation apparatus 101 includes a mist-forming unit 120 that generates mist by misting a raw material solution, a carrier gas supply unit 130 that supplies a carrier gas for transporting the mist, a film formation unit 140 that heat-treats the mist to form a film on a substrate, a transport unit 109 that connects the mist-forming unit 120 and the film formation unit 140 and transports the mist by the carrier gas, and an exhaust unit 170 that exhausts exhaust gas from the film formation unit 140. The film formation apparatus 101 may also include a control unit (not shown) that controls all or part of the film formation apparatus 101, thereby controlling its operation.

[0054] (Mist generating section) In the mist generating section 120, the raw material solution is turned into mist to generate mist. The mist generating means is not particularly limited as long as it can turn the raw material solution into mist, and any known mist generating means may be used, but it is preferable to use a mist generating means that uses ultrasonic vibrations, as this allows for more stable mist generation. An example of such a mist-generating unit 120 is shown in FIG. 2. For example, the mist-generating unit 120 may include a mist source 104 that contains raw solution 104a, a container 105 that contains a medium capable of transmitting ultrasonic vibrations, such as water 105a, and an ultrasonic vibrator 106 attached to the bottom of the container 105. More specifically, the mist source 104, which is a container that contains the raw solution 104a, is housed in the container 105 that contains the water 105a using a support (not shown). The bottom of the container 105 is equipped with an ultrasonic vibrator 106, which is connected to an oscillator 116. When the oscillator 116 is activated, the ultrasonic vibrator 106 vibrates, and ultrasonic waves propagate through the water 105a into the mist source 104, turning the raw solution 104a into mist.

[0055] (Carrier gas supply unit) The carrier gas supply unit 130 has a carrier gas source 102a that supplies a carrier gas (main carrier gas), and may also be equipped with a flow rate control valve 103a for adjusting the flow rate of the main carrier gas delivered from the carrier gas source 102a. It may also be equipped with a dilution carrier gas source 102b that supplies a carrier gas for dilution (dilution carrier gas) as needed, and a flow rate control valve 103b for adjusting the flow rate of the dilution carrier gas delivered from the dilution carrier gas source 102b. The type of carrier gas is not particularly limited and can be selected appropriately depending on the film to be formed. Examples include inert gases such as oxygen, ozone, nitrogen, and argon, and reducing gases such as hydrogen gas and forming gas. The type of carrier gas may be one type or two or more types. For example, a diluted gas obtained by diluting the same gas as the first carrier gas with another gas (e.g., diluted 10 times) may be further used as the second carrier gas, or air may be used. Furthermore, the number of supply points for the carrier gas may not be limited to one, but may be two or more. The flow rate of the carrier gas is not particularly limited. For example, when forming a film on a substrate with a diameter of 4 inches (10 cm), the flow rate is preferably 1 to 80 L / min, and more preferably 4 to 40 L / min. Note that this carrier gas flow rate Q is a value measured at 20°C. When measured at other temperatures or when a different type of flow rate (mass flow rate, etc.) is measured, it can be converted to a volumetric flow rate at 20°C using the gas state equation.

[0056] (film formation section, exhaust section) In the film formation unit 140, the mist is heated to cause a thermal reaction, thereby forming a film on a portion or all of the surface of the substrate 110. The film formation unit 140 may be partially or entirely enclosed. For example, as shown in FIG. 1, the entire film formation unit 140 may be enclosed to form a film formation chamber 107. The film formation chamber 107 is not limited to a completely enclosed shape, and may have gaps and only enclose a portion of the film formation unit. The film formation unit 140 is provided with a mounting portion 112 on which a substrate is placed. The film formation unit 140 has a substrate 110 placed therein and may be provided with a hot plate 108 for heating the substrate 110. The hot plate 108 may be provided inside the film formation chamber 107 as shown in FIG. 1, or may be provided outside the film formation chamber 107.

[0057] Furthermore, the film forming section 140 is provided with a nozzle 150 above the mounting section 112 for supplying mist to the substrate 110, as shown in FIG.

[0058] An example of the nozzle 150 is shown in Figure 4. The nozzle 150 includes a connection part 151 that connects the transport part 109 and the nozzle 150, and a nozzle opening surface (also simply referred to as the opening surface) 152 for spraying mist. The number of nozzles and the number of openings are not particularly limited as long as they are at least 1. As shown in Figure 5, a plurality of nozzles may be provided (nozzle 150a), or as shown in Figure 6, a plurality of openings may be provided (nozzle 150b). Furthermore, the angle formed by the plane including the nozzle opening surface 152 and the plane including the substrate 110 is not particularly limited. A nozzle may be provided with a nozzle opening surface that is inclined so that the mist flows more easily in a specific direction, but it is preferable to provide the nozzle opening surface parallel to the surface of the mounting portion 112 on which the substrate 110 is mounted, as shown in Figure 3. This is because a film with better in-plane film thickness uniformity can be formed with a simpler structure. The area of ​​the nozzle opening surface 152 is S [cm 2 ], the flow rate of the carrier gas is Q [L / min], and the difference in height between the nozzle opening surface 152 and the substrate 110 (for example, the longest distance between a point in the nozzle opening surface 152 and the surface of the substrate 110) is H [cm], then SH / Q should be 0.015 or more, and preferably 0.1 to 20. When SH / Q≧0.015, the film has better in-plane film thickness uniformity. At this time, the velocity of the gas in the direction perpendicular to the substrate at the nozzle opening surface 152 is preferably 0.01 to 8.0 m / s, more preferably 0.1 to 2.0 m / s. In this case, the area S of the nozzle opening surface 152 is preferably 0.1 or more and 400 or less. The difference H in height between the nozzle opening surface 152 and the substrate 110 is preferably 0.1 or more and 6.0 or less, and more preferably 0.2 or more and 3.0 or less. This is because the deposited film will have better in-plane film thickness uniformity. The area of ​​the nozzle opening surface 152 is S [cm 2 ], the area of ​​the substrate is A [cm 2 ], S / A≦0.3 is preferable, and 0.004≦S / A≦0.15 is more preferable. When S / A≦0.3, the film has better in-plane film thickness uniformity. In addition, when the area A of the substrate is 10 cm 2 It is preferable that it is 50cm or more. 2 The above is more preferable, and there is no particular upper limit. The larger the area of ​​the substrate, the larger the area of ​​the film that can be obtained in one film formation, and therefore, the larger the area of ​​the substrate is, the more suitable it is for mass production. The shape of the nozzle opening surface 152 is not particularly limited. Possible shapes include polygon, circle, and ellipse, but a square shape is preferable, and a rectangle is more preferable. When the shape of the nozzle opening surface 152 is rectangular, the long axis length of the nozzle opening surface 152 is L [cm], and the maximum length of the substrate in the nozzle long axis direction is R [cm], and L / R ≧ 1 is preferable. This is because if L / R ≧ 1, a film with good in-plane film thickness uniformity can be formed on a large-area substrate. There is no particular upper limit to L / R, but since the larger L / R is, the more mist is not supplied to the substrate, it is preferable to set it to 3 or less.

[0059] 3, the top plate 153 may be installed above the mounting portion 112, and there are no particular limitations on its shape, size, installation position, installation height, installation method, material, or number. For example, if the film formation chamber 107 is provided, the top plate 153 may be provided between the ceiling of the film formation chamber 107 and the substrate 110 on the mounting portion 112. By providing the top plate 153, the flow of mist is less likely to be disturbed by the flow of ambient gas due to thermal convection during film formation processing by heat treatment, and the mist supplied from the nozzle 150 is rectified and supplied onto the substrate 110, making it possible to form a film with excellent in-plane film thickness uniformity. As mentioned above, the positions of the nozzle 150 and the top plate 153 are not particularly limited as long as they are above the mounting portion 112, but for example, as shown in Fig. 3, they can each be disposed vertically above the upper surface of the hot plate 108 on which the substrate 110 is placed. Such an arrangement is simple and convenient, and enables a film with sufficiently excellent film thickness uniformity to be formed on the substrate. The top plate 153 may also be equipped with a temperature adjustment mechanism (not shown) that can adjust the temperature of the surface (bottom surface) of the substrate 110 facing the mounting portion 112. If the temperature of this surface (bottom surface) is too high, evaporation of the mist is promoted, increasing the film thickness at positions on the substrate 110 away from the nozzle opening surface 152, while if the temperature is too low, evaporation of the mist is slowed down, decreasing the film thickness at positions close to the nozzle opening surface 152. It is preferable to control the temperature at around 40 to 120°C.

[0060] The top plate may be polygonal, semicircular, circular, or elliptical in shape, but a rectangular shape is preferable, as this provides good symmetry and the deposited film has good in-plane uniformity in thickness. The top plate may be in contact with the side of the nozzle, or a gap may be provided. For example, a hole may be formed in the top plate (i.e., doughnut-shaped), and the nozzle may be inserted into the hole. In this case, the distance between the top plate and the side of the nozzle is preferably 2 cm or less, preferably 1 cm or less, and more preferably 0 cm. This is because the film will have good in-plane uniformity in thickness. The distance between the top plate and the nozzle opening surface is set to 0 cm if the nozzle and top plate are integrated, but if they are separate, the distance is the shortest distance between the top plate and the nozzle opening surface minus the nozzle wall thickness. For example, if the distance between the top plate and the nozzle opening surface is 2.5 cm, the nozzle wall is included in the shortest distance, and the nozzle wall thickness is 0.5 cm, then the shortest distance between the top plate and the nozzle opening surface is 2.0 cm.

[0061] The top plate may be suspended from the film formation chamber by fixtures 154a or the like, as in the case of top plate 153a in Fig. 7 (film formation unit 140a), but it is preferable to fix it to the side of the nozzle as in Fig. 3. This is because the film to be formed will have good in-plane uniformity in film thickness. Furthermore, the top plate may be partially or entirely curved or bent so that the mist can easily flow in a specific direction, as in top plate 153b in Fig. 8 (film forming unit 140b), but is preferably placed parallel to mounting unit 112, as in Fig. 3. More specifically, top plate 153 is preferably placed so that the surface of mounting unit 112 on which substrate 110 is placed is parallel to the bottom surface of top plate 153. This is because the film formed will have good in-plane uniformity in film thickness. The top plate may be installed in the same plane as the nozzle opening, or may be closer to the substrate 110 than the nozzle opening as in the top plate 153c suspended from fixture 154b in FIG. 9 (film forming unit 140c), or may be farther from the substrate 110 than the nozzle opening as in the top plate 153d in FIG. 10 (film forming unit 140d). However, it is more preferable to install the top plate in the same plane as the nozzle opening as this will result in a film having better in-plane thickness uniformity. In addition, the film forming section 140 may be equipped with a position adjustment mechanism (not shown) that can appropriately adjust the difference in height H [cm] between the nozzle opening surface 152 and the substrate 110, and the difference in height I [cm] between the top plate 153 and the surface of the mounting section 112 on which the substrate 110 is placed.

[0062] The thickness of the top plate is not particularly limited, but is preferably 2 mm or more, since this prevents deformation due to heating during film formation. The number of top plates is not particularly limited. As shown in Fig. 3, there may be one top plate for one nozzle, or as shown in Fig. 11 (film forming unit 140e), there may be multiple top plates (two top plates 153e in this example) for one nozzle. The material of the top plate is not particularly limited, and possible materials include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, and glass.

[0063] Furthermore, the difference in height I [cm] between the bottom surface of the top plate 153 and the surface of the mounting portion 112 on which the substrate is placed (for example, the shortest difference in height) is not particularly limited, but is preferably 0.15 cm or more and 6.05 cm or less, more preferably 0.5 cm or more and 3.0 cm or less, and even more preferably 1.0 cm or more and 2.0 cm or less. This is because the deposited film will have even better in-plane film thickness uniformity. In addition, the area of ​​the bottom of the tabletop (the total area if multiple tabletops are installed) is B [cm 2 ], the area of ​​the substrate is A [cm 2], it is preferable that B / A≧0.5, and more preferably 1 or more. When B / A≧0.5, the resulting film has good in-plane uniformity of film thickness. Furthermore, B should be 40 or more. Within these numerical ranges, a film with even better in-plane uniformity of film thickness can be formed. Furthermore, there are no particular restrictions on the upper limits of B / A or B. This is because if it is greater than the above numerical values, the rectifying effect of the top plate is exerted. However, it is preferable that B / A is 100 or less. Furthermore, an example of the upper limit of B can be 3000. This is to prevent the device from becoming larger than necessary.

[0064] The film forming unit 140 may also be provided with a movement mechanism that moves the substrate 110 below the nozzle 150. An example of a film forming unit 140f equipped with a movement mechanism 160 is shown in Figure 12. The direction in which the substrate is moved is not particularly limited.

[0065] 13 and 14 show views of the film forming unit 140 equipped with a moving mechanism 160 as viewed from above the mounting unit. One method, as shown in FIG. 13 (moving mechanism 160a), includes a moving stage 161a on which the substrate 110 and hot plate 108 are mounted, and the substrate 110 and hot plate 108 move back and forth under the nozzle 150 and two rectangular top plates 153f. Another method, as shown in FIG. 14 (moving mechanism 160b), includes a moving stage 161b on which the substrate 110 and hot plate 108 are mounted, and the substrate 110 and hot plate 108 rotate and move under the nozzle 150 and two top plates 153g shaped like a ring in half. A mechanism for rotating the substrate may also be provided to rotate the substrate. 14, multiple substrates 110 and nozzles 150 may be placed on the film forming unit 140, or multiple substrates may be placed on the film forming unit 140 shown in FIG. 13. Such a structure allows film formation on many substrates at once while maintaining uniformity in the film thickness, making it even more suitable for mass production.

[0066] Furthermore, when the substrate moving mechanism 160 is provided, the speed and range of substrate movement are not particularly limited, but the number of times a substrate passes under the nozzle is preferably 0.1 times or more per minute, more preferably 0.5 times or more, and even more preferably 1 time or more. By setting the number of times to 0.1 or more, the rising air current caused by localized mist evaporation can be prevented from significantly affecting the supplied gas, reducing the rectifying effect of the top plate, thereby more reliably preventing a decrease in film thickness uniformity. Furthermore, while there is no particular upper limit to the number of times, an increase in the number of times can cause the substrate to become unstable due to inertial forces, so a number of times of 120 times or less is preferable, and 60 times or less is more preferable. More specifically, in the case of a moving mechanism such as that shown in FIG. 13, where v [mm / min] is the substrate movement width D [mm] and v / D [ / min] is the substrate movement speed, v / D [ / min] is preferably 0.1 or greater, more preferably 0.5 to 120, and even more preferably 1 to 60. D is not particularly limited, and is preferably equal to or greater than the diameter [mm] of the substrate (e.g., 100 or greater if the substrate diameter is 4 inches), with no particular upper limit. Increasing D allows for deposition on a large number of substrates per nozzle. However, since the deposition rate per substrate decreases, it is preferable to limit the number of substrates per nozzle to 1,000 mm or less, which is more productive. v is not particularly limited. It is preferably 10 mm / min to 30,000 mm / min, more preferably 30 mm / min to 12,000 mm / min, and even more preferably 60 mm / min to 6,000 mm / min. In the case of a rotary type moving mechanism such as that shown in FIG. 14, the rotation speed is preferably 0.1 rpm or more, more preferably 0.5 to 120 rpm, and even more preferably 1 to 60 rpm.

[0067] In addition, the film forming section 140 (film forming chamber 107) is equipped with an exhaust section 170 for rectifying the flow of the mist supplied onto the substrate 110 together with the carrier gas so that the mist is used for film formation, and the subsequent gas (referred to as exhaust gas, including mist not used for film formation, gas generated during film formation, carrier gas, etc.) flows outside the substrate 110, and the exhaust gas is exhausted from the film forming section 140 through the exhaust section 170. The straightening effect of the top plate 153 and the synergistic effect of the convection generated by the supply of mist from the nozzle 150 and the exhaust of exhaust gas from the exhaust section 170 generate a uniform gas flow above the substrate 110 that is parallel to the surface of the substrate 110, making it possible to produce a uniform film on the substrate 110. The shape and configuration of the exhaust unit 170 are not particularly limited as long as it is configured to exhaust the exhaust gas from the film formation unit 140. For example, as shown in Fig. 1, an exhaust port 111 may be provided on the side of the substrate 110 in the film formation chamber 107 to perform forced exhaust. A configuration in which a carrier gas or the like supplied from the nozzle 150 between the top plate 153 and the substrate 110 flows to the outside of the substrate 110 is particularly preferable. The outside of the substrate 110 here refers to a region that does not include the substrate 110 in the xy plane at all z angles, with the normal direction of the plane including the substrate surface being the z axis. The exhaust unit 170 can be the exhaust port 111 itself provided in the film formation chamber 107 as described above, or it can be the exhaust port 111 plus a means for forced exhaust. An example of such an exhaust unit 170 is shown in FIG. 16. For example, an exhaust unit 172 provided outside the film formation chamber 107 forcibly exhausts the gas inside the film formation chamber 107 from the exhaust port 111 provided on the side of the film formation chamber 107 through an exhaust duct 171. The exhaust unit 172 is equipped with an exhaust flow rate control valve 173 for adjusting the exhaust flow rate, so that the exhaust flow rate can be adjusted. Although the exhaust flow rate is not particularly limited, when the flow rate of the carrier gas supplied from the nozzle 150 is Q [L / min] and the exhaust volume exhausted from the exhaust unit 170 is E [L / min], E / Q is preferably 5 or less, more preferably 0.1 or more and 1 or less. This is because a film with good in-plane film thickness uniformity is obtained. Furthermore, at this time, E exhausted from exhaust unit 170 can be measured at 20°C using a flow meter at exhaust port 111, or calculated as the product of the linear velocity measured using an anemometer and the area of ​​the opening surface of exhaust port 111. When the wind velocity is measured at another temperature, or the flow rate is measured by another method or at another temperature, it can be converted to a volumetric flow rate at 20°C using the gas state equation. The shape of the exhaust port 111 is not particularly limited and may be circular, rectangular, or the like. 3, the exhaust section 170 may be provided in one place, or in two or more places as shown in FIG. 1, but when providing two or more places, it is preferable to provide them at symmetrical positions with respect to the center of the nozzle opening surface, as this allows deposition of a film with good in-plane film thickness uniformity. Furthermore, exhaust unit 170 may be provided with a temperature control mechanism (not shown) that controls the temperature of part or the entire exhaust unit in order to suppress the precipitation of solids within the exhaust unit. Such a temperature control mechanism suppresses the precipitation of solids within exhaust unit 170, making it easier to control the exhaust flow rate. Furthermore, the material of the components constituting the exhaust section 170 is not particularly limited, and examples thereof include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, and boron nitride. Boron nitride is preferable because it can prevent the flow of exhaust gas from becoming uneven due to rust or solid precipitation caused by unintended reactions with unreacted raw materials. Furthermore, as described above, when the film formation chamber 107 includes the moving mechanism 160, the exhaust port 111 may be provided on the moving mechanism 160, so that the exhaust port 111 (exhaust unit 170) can be moved. The film formation chamber 107 may be completely enclosed and have an exhaust port 111 on its wall, or may only be partially enclosed (i.e., have a gap) and have an exhaust section (exhaust port 111) in addition to the gap. In the latter case, the film can have a better in-plane film thickness uniformity. Furthermore, the thermal reaction of the mist in the film forming section 140 is not particularly limited as long as the mist reacts due to heating. The reaction conditions can be set appropriately depending on the raw material and the film to be formed. For example, the heating temperature can be set in the range of 120 to 600°C, preferably in the range of 200 to 600°C, and more preferably in the range of 300 to 550°C. The heating temperature is T [°C], and the area of ​​the nozzle opening surface 152 is S [cm 2] and the flow rate of the carrier gas is Q [L / min], ST / Q is preferably 40 or more, and more preferably 100 to 2000. When ST / Q≧40, the film has better in-plane film thickness uniformity. The thermal reaction may be carried out under any of the following atmospheres: vacuum, non-oxygen atmosphere, reducing gas atmosphere, air atmosphere, and oxygen atmosphere, and may be appropriately set depending on the film to be formed. The reaction pressure may be atmospheric pressure, elevated pressure, or reduced pressure, but film formation under atmospheric pressure is preferred because it simplifies the device configuration.

[0068] (Transportation section) The transfer unit 109 connects the mist generation unit 120 and the film formation unit 140. Mist is transferred by a carrier gas from the mist generation source 104 of the mist generation unit 120 to the nozzle 150 of the film formation unit 140 via the transfer unit 109. The transfer unit 109 can be, for example, a supply pipe 109a. The supply pipe 109a can be, for example, a quartz pipe or a resin tube.

[0069] (Raw material solution) The raw material solution (aqueous solution) 104a is not particularly limited as long as it contains a material that can be turned into mist, and may be an inorganic material or an organic material. A solution of a metal or metal compound is preferably used as the raw material solution, and one or more metals selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, and cobalt can be used. The raw material solution is not particularly limited as long as it can turn the metal solution into a mist. A suitable raw material solution is one in which the metal is dissolved or dispersed in an organic solvent or water in the form of a complex or salt. Examples of complexes include acetylacetonate complexes, carbonyl complexes, ammine complexes, and hydride complexes. Examples of salts include metal chlorides, metal bromides, and metal iodides. Furthermore, solutions in which the metals are dissolved in hydrobromic acid, hydrochloric acid, hydroiodic acid, or the like can also be used as aqueous salt solutions. The solute concentration is preferably 0.01 to 1 mol / L. The raw material solution may also contain additives such as halogen-containing compounds (e.g., hydrohalic acid) or oxidizing agents. Examples of hydrohalic acids include hydrobromic acid, hydrochloric acid, and hydroiodic acid, with hydrobromic acid and hydroiodic acid being preferred. Examples of oxidizing agents include peroxides such as hydrogen peroxide (H2O2), sodium peroxide (Na2O2), barium peroxide (BaO2), and benzoyl peroxide (C6H5CO)2O2, as well as hypochlorous acid (HClO), perchloric acid, nitric acid, ozone water, and organic peroxides such as peracetic acid and nitrobenzene. Furthermore, 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, and niobium, and p-type dopants such as copper, silver, tin, iridium, and rhodium. The dopant concentration is, for example, about 1.0 × 10 -9 It may be up to 1.0 mol / L, and may be about 1.0 × 10 -7 The concentration may be as low as 0.01 mol / L or less, or as high as about 0.01 mol / L or more.

[0070] (substrate) The substrate 110 is not particularly limited as long as it can be used to form a film and can support the film. The material of the substrate 110 is also not particularly limited, and any known substrate can be used, and it may be an organic compound or an inorganic compound. Examples of the material include, but are not limited to, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, silicon, sapphire, quartz, glass, gallium oxide, lithium niobate, and lithium tantalate. The thickness of the substrate is not particularly limited, but is preferably 10 to 2000 μm, and more preferably 50 to 800 μm.

[0071] The film formation may be carried out directly on the substrate or may be laminated on an intermediate layer formed on the substrate. The intermediate layer is not particularly limited. For example, it can be mainly composed of an oxide containing any one of aluminum, titanium, vanadium, chromium, iron, gallium, rhodium, indium, and iridium. More specifically, it is Al2O3, Ti2O3, V2O3, Cr2O3, Fe2O3, Ga2O3, Rh2O3, In2O3, Ir2O3. Also, when two elements selected from the above metal elements are designated as A and B, a binary metal oxide represented by (A x B 1-x )2O3 (0 < x < 1), or when three elements selected from the above metal elements are designated as A, B, and C, a ternary metal oxide represented by (A x B y C 1-x-y )2O3 (0 < x < 1, 0 < y < 1) can be used.

[0072] Further, the substrate can be, for example, one having a film-forming surface area of 50 cm 2 or more, or a diameter of 4 inches (100 mm) or more. This is preferable because a film with good in-plane uniformity of film thickness can be formed over a large area. The upper limit of the area or diameter of the substrate is not particularly limited. For example, the area can be 750 cm 2 , or the diameter can be 12 inches (300 mm).

[0073] (Film Formation Method) Next, an example of the film formation method according to the present invention will be described below with reference to FIG. 1. First, the raw material solution 104a is housed in the mist generation source 104 of the mist generation unit 120, the substrate (crystalline substrate) 110 is placed on the hot plate 108, and the hot plate 108 is operated.

[0074] Next, the flow rate control valves 103a and 103b are opened, and carrier gas is supplied into the film formation chamber 107 from the carrier gas source 102a (main carrier gas) and the dilution carrier gas source 102b (dilution carrier gas). The atmosphere in the film formation chamber 107 is sufficiently replaced with the carrier gas, and the flow rates of the main carrier gas and the dilution carrier gas are respectively adjusted and controlled.

[0075] In the mist generating step, the ultrasonic vibrator 106 is vibrated, and the vibration is propagated to the raw material solution 104a through the water 105a, thereby turning the raw material solution 104a into mist and generating the mist. Next, in the mist transport step of transporting the mist by a carrier gas, the mist is transported by the carrier gas from the mist-forming unit 120 to the film-forming unit 140 via the transport unit 109 and introduced into the film-forming chamber 107 . In the film formation process, mist is supplied from a nozzle 150 provided above the mounting section 112 (hot plate 108 on which substrate 110 is placed) to between a top plate 153 provided above the mounting section 112 and the substrate 110. The mist is then rectified by exhaust from the installed top plate 153 and exhaust section 170 (exhaust port 111, etc.) and supplied onto the substrate 110, where it is thermally treated by the heat of the hot plate 108 in the film formation chamber 107, causing a thermal reaction and forming a film on the substrate 110.

[0076] This film deposition method makes it possible to deposit a film with excellent in-plane film thickness uniformity compared to conventional methods that do not use the top plate 153 . In addition, depositing a film while moving the substrate 110 below the nozzle 150 using the moving mechanism 160 is effective when forming a film over a large area, and is also effective in depositing a superior film with a more uniform in-plane thickness.

[0077] In the present invention, after the film is formed, an annealing treatment may be performed. The temperature of the annealing treatment is not particularly limited, but is preferably 600°C or less, more preferably 550°C or less, so as not to impair the crystallinity of the film. The treatment time of the annealing treatment is not particularly limited, but is preferably 10 seconds to 10 hours, more preferably 10 seconds to 1 hour. [Example]

[0078] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Example 1 In this example, a film forming apparatus as shown in FIG. 1 was used. A top plate 153 is fixed in the same plane as the nozzle opening surface 152 so as to contact the side surface of the nozzle 150. The area of ​​the top plate is B [cm 2 ], B=450, and when the difference in height between the mounting surface of mounting portion 112 (the upper surface of hot plate 108) and the bottom surface of top plate 153 is I [cm], I=0.95. The thickness of the top plate is 4 mm. The top plate 153 has a rectangular shape as shown in FIG. 17 (also referred to as a top plate 153i), and the nozzle 150 is inserted into a hole formed in the center.

[0079] Gallium iodide was dissolved in water to prepare a 0.05 mol / L aqueous solution, which was used as raw material solution 104a. The raw material solution 104a obtained as described above was placed in mist generating source 104. The temperature of the solution at this time was 25°C. Next, a 4-inch (100 mm diameter) c-plane sapphire substrate as substrate 110 was placed on hot plate 108 in film formation chamber 107, and hot plate 108 was operated to raise the temperature to 500°C. Next, the flow control valves 103a and 103b were opened to supply nitrogen gas as a carrier gas from the carrier gas source 102a (main carrier gas) and the dilution carrier gas supply source 102b (dilution carrier gas) into the film formation chamber 107, and the atmosphere in the film formation chamber 107 was thoroughly replaced with these carrier gases, while the flow rate of the main carrier gas was adjusted to 12 L / min and the flow rate of the dilution carrier gas was adjusted to 12 L / min, respectively. 16, the exhaust flow rate adjustment valve 173 was adjusted so that the exhaust amount E [L / min] at the exhaust port 111 was 24. At this time, E / Q=1.

[0080] 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, thereby turning the raw material solution 104a into mist and generating mist. This mist was supplied to the substrate 110 by a carrier gas through the supply pipe 109a and the nozzle 150. The nozzle 150 used had a nozzle opening surface 152 with a rectangular shape, and the area of ​​the nozzle opening surface 152 was S [cm 2 ], the flow rate of the carrier gas is Q [L / min], and the difference in height between the nozzle opening surface 152 and the substrate 110 (the longest distance between a point in the nozzle opening surface 152 and the surface of the substrate 110) is H [cm]. Adjustments were made so that SH / Q = 0.07. In this case, S = 1.92, H = 0.9, and Q = 24. Then, under atmospheric pressure and at 500°C, the mist was thermally reacted in the film formation chamber 107 while gas was being exhausted from the exhaust port 111, to form a thin film of gallium oxide (α-Ga2O3) having a corundum structure on the substrate 110. The film formation time was 30 minutes.

[0081] When the heat treatment temperature is T [℃], ST / Q = 40, and the area of ​​the substrate is A [cm 2 ], S / A=0.024, the long axis length of the nozzle opening surface 152 is L [cm], and the maximum length of the substrate in the nozzle long axis direction is R [cm], so L / R=1.2. In this case, T=500, A=78.5, L=12, and R=10. Also, B / A=5.7. The substrate and hot plate were reciprocated by a moving mechanism 160a as shown in FIG. 13 at a speed of 15 cm / min so as to pass under the nozzle once per minute.

[0082] (Comparative Example 1) The same procedure as in Example 1 was carried out except that the top plate 153 was not used.

[0083] Example 2 The area S of the nozzle opening surface 152 is 6.0 cm 2 The same procedure as in Example 1 was carried out, except that the difference in height H between the nozzle opening surface 152 and the substrate 110 was changed to 2.0 cm, the difference in height I between the bottom surface of the top plate 153 and the mounting surface of the mounting portion 112 was changed to 2.05 cm, and SH / Q = 0.5, ST / Q = 125, and S / A = 0.076.

[0084] Example 3 The same procedure as in Example 1 was carried out except that the fixing position of the top plate was changed and the shortest distance I between the placement portion 112 and the bottom surface of the top plate 153 was set to 2.05 cm.

[0085] Example 4 8, the same procedure as in Example 1 was carried out except that a curved top plate 153b was used. At this time, the difference in height between the mounting surface of mounting portion 112 and the center of the bottom surface of top plate 153b was I=0.95, and the difference in height between the edge of the bottom surface of top plate 153b and the mounting surface of the mounting portion was 1.25 cm.

[0086] Example 5 Film formation was carried out in the same manner as in Example 1, except that the area B of the bottom surface of the top plate 153 was set to 40. At this time, B / A was 0.5.

[0087] Example 6 The area S of the nozzle opening surface 152 is 6.0 cm 2 The same procedure as in Example 1 was carried out, except that the difference in height H between the nozzle opening surface 152 and the substrate 110 was changed to 0.1 cm, the difference in height I between the bottom surface of the top plate 153 and the mounting surface of the mounting portion 112 was changed to 0.15 cm, the total flow rate of the carrier gas was set to 12 L / min, SH / Q = 0.05, ST / Q = 250, and S / A = 0.076.

[0088] Example 7 The area S of the nozzle opening surface 152 is 6.0 cm 2 The same procedure as in Example 1 was performed, except that the difference in height H between the nozzle opening surface 152 and the substrate 110 was changed to 6.0 cm, the difference in height I between the bottom surface of the top plate 153 and the mounting surface of the mounting portion 112 was changed to 6.05 cm, the total flow rate of the carrier gas was set to 72 L / min, SH / Q = 0.5, ST / Q = 41.7, and S / A = 0.076.

[0089] Example 8 The same procedure as in Example 1 was carried out except that an aluminum acetylacetonate complex was dissolved in a hydrochloric acid solution to prepare a 0.05 mol / L solution, which was used as a raw material solution.

[0090] Example 9 The same procedure as in Example 1 was carried out except that gallium nitrate was dissolved in water to prepare a 0.05 mol / L solution, which was used as the raw material solution, E was set to 188.4 L / min, and E / Q was set to 7.9.

[0091] Example 10 The experiment was carried out in the same manner as in Example 1, except that the shape of the nozzle opening surface 152 was a circle with a diameter of 2 inches (5 cm), the substrate was not moved (the nozzle and top plate were always positioned vertically above the substrate), the flow rate of the carrier gas was changed to a total of 80 L / min, a ring-shaped top plate 153h was used, which consisted of a circular hole with a diameter of 6 cm and a circle with a diameter of 10 cm, as shown in Figure 15, and the nozzle was inserted into the circular hole in the top plate, leaving a gap (0.5 cm) between the side of the nozzle and the top plate. The values ​​were SH / Q = 0.22, ST / Q = 123, S / A = 0.25, and L / R = 0.5.

[0092] Example 11 The same procedures as in Example 1 were carried out except that the difference in height H between the nozzle opening surface 152 and the substrate 110 was changed to 6.5 cm, the difference in height I between the bottom surface of the top plate 153 and the mounting surface of the mounting portion 112 was changed to 6.55 cm, and the total flow rate of the carrier gas was changed to 72 L / min. At this time, SH / Q=0.17 and ST / Q=13.3.

[0093] Example 12 Except for changing the size of the hole in the center of the top plate 153 (153i) and providing a gap of 2 cm between the top plate and the side of the nozzle, the same procedure was carried out as in Example 1. In this case, B=420 and B / A=5.4.

[0094] Example 13 18, the same procedure as in Example 12 was carried out, except that an exhaust port 111 was provided above the nozzle, E was set to 120 L / min, and E / Q was set to 5. Note that mist and carrier gas were supplied from the nozzle to form a film on the substrate, and exhaust gas was exhausted from the exhaust port 111 through the gap between the top plate and the side surface of the nozzle.

[0095] (film thickness distribution measurement) The film thickness of the thin film formed on the substrate 110 was measured using a step gauge at 50 measurement points on the surface of the substrate 110. The average film thickness was calculated from each measurement value. The film thickness distribution calculated as (film thickness distribution [±%]) = (maximum film thickness - minimum film thickness) / (average film thickness) / 2 × 100 is shown in Table 1. Similar results were obtained when the film thickness of the thin film formed on the substrate 110 was measured at 25 points on the surface of the substrate 110 using an optical interference film thickness meter F50.

[0096] [Table 1]

[0097] A comparison of Examples 1 to 13 with Comparative Example 1 revealed that excellent in-plane uniformity of film thickness can be achieved by using a film formation apparatus equipped with a mist generating section, a carrier gas supply section, a film formation section, and an exhaust section, and equipped with a nozzle for supplying mist onto a substrate above a mounting section on which a substrate is placed, which is installed within the film formation section, and a top plate for rectifying the mist.

[0098] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A film forming apparatus for forming a film on a substrate by heat-treating a mist of raw material solution, a mist generating unit that generates mist by misting the raw material solution; a carrier gas supply unit that supplies a carrier gas that carries the mist generated in the mist generating unit; a film forming unit including a mounting unit for mounting the substrate thereon, and the mist carried by the carrier gas is supplied onto the substrate; an exhaust unit that exhausts exhaust gas from the film forming unit; Equipped with Above the placement unit in the film forming unit, a nozzle for supplying the mist onto the substrate; a top plate that rectifies the mist supplied from the nozzle along the substrate; The film forming apparatus further comprises:

2. 2. The film forming apparatus according to claim 1, wherein the nozzle and the top plate are installed vertically above the mounting portion.

3. 3. The film forming apparatus according to claim 1, wherein the top plate is disposed in contact with a side surface of the nozzle.

4. 4. The film forming apparatus according to claim 1, wherein the top plate is installed in the same plane as an opening surface of the nozzle.

5. 5. The film forming apparatus according to claim 1, wherein the top plate is installed so that a bottom surface of the top plate is parallel to a surface of the mounting portion on which the substrate is placed.

6. 6. A film forming apparatus according to claim 1, wherein the top plate is installed so that the difference in height between the bottom surface of the top plate and the surface of the mounting section on which the substrate is placed is 0.15 cm or more and 6.05 cm or less.

7. 7. The film forming apparatus according to claim 1, wherein the nozzle is installed so that the difference in height between the opening surface of the nozzle and the substrate placed on the placement section is 0.1 cm or more and 6.0 cm or less.

8. The area of ​​the bottom surface of the top plate is B [cm ２ 8. The film forming apparatus according to claim 1, wherein B≧40 when B is 1 / (B / 2) / (C / D).

9. The area of ​​the substrate is A [cm ２ ], the area of ​​the bottom surface of the top plate is B [cm ２ 9. The film forming apparatus according to claim 1, wherein B / A≧0.5 when B / A is 0.5 or more.

10. 10. The film forming apparatus according to claim 1, further comprising a moving mechanism that moves the substrate below the nozzle.

11. 11. The film forming apparatus according to claim 1, wherein the raw material solution contains gallium.

12. 12. The film forming apparatus according to claim 1, wherein the raw material solution contains a halogen.

13. A film formation method for forming a film on a substrate by heat-treating a mist of a raw material solution, comprising: a mist generating step of misting the raw material solution to generate mist; a mist transport step of transporting the mist to a film forming unit by a carrier gas; a film-forming step of supplying the mist onto the substrate placed on a placement unit in the film-forming unit to perform heat treatment and film formation while exhausting exhaust gas; Including, In the film forming step, A film forming method characterized in that the mist is supplied onto the substrate from a nozzle provided above the placement section between the substrate and a top plate provided above the placement section, thereby supplying the mist onto the substrate in a rectified manner along the substrate.

14. 14. The film forming method according to claim 13, wherein the nozzle and the top plate are installed vertically above the placement portion.

15. 15. The film forming method according to claim 13, wherein the top plate is installed in contact with a side surface of the nozzle.

16. 16. The film forming method according to claim 13, wherein the top plate is placed in the same plane as an opening surface of the nozzle.

17. 17. The film deposition method according to claim 13, wherein the top plate is placed so that a bottom surface of the top plate is parallel to a surface of the mounting section on which the substrate is placed.

18. 18. A film forming method according to claim 13, wherein the top plate is positioned so that the difference in height between the bottom surface of the top plate and the surface of the mounting section on which the substrate is placed is 0.15 cm or more and 6.05 cm or less.

19. 19. The film forming method according to claim 13, wherein the nozzle is disposed so that the difference in height between the opening surface of the nozzle and the substrate placed on the placement section is 0.1 cm or more and 6.0 cm or less.

20. The area of ​​the bottom surface of the top plate is B [cm ２ 20. The film forming method according to claim 13, wherein B≧40 when B is 0.1 or more.

21. The area of ​​the substrate is A [cm ２ ], the area of ​​the bottom surface of the top plate is B [cm ２ 21. The film forming method according to claim 13, wherein B / A≧0.5 when B / A≧0.

5.

22. 22. The film forming method according to claim 13, wherein the substrate is moved below the nozzle in the film forming step.

23. 23. The film forming method according to claim 13, wherein the raw material solution contains gallium.

24. 24. The film forming method according to claim 13, wherein the raw material solution contains a halogen.

25. 25. The film forming method according to claim 13, wherein when the flow rate of the carrier gas supplied from the nozzle is Q [L / min] and the flow rate of the exhaust gas is E [L / min], E / Q is 5 or less.

26. The substrate is set so that the area of ​​the surface on which the film is to be formed is 50 cm ２ 26. The film forming method according to claim 13, wherein the diameter of the nozzle is 4 inches (100 mm) or more.

27. A gallium oxide film having a corundum structure, The gallium oxide film has an area of ​​50 cm ２ or larger, or with a diameter of 4 inches (100 mm) or larger, A gallium oxide film, characterized in that the in-plane distribution of the film thickness of the gallium oxide film is between ±3.1% and ±11.7%.

28. A laminate of a gallium oxide film having a corundum structure and a substrate, The gallium oxide film of the laminate has an area of ​​50 cm ２ or larger, or with a diameter of 4 inches (100 mm) or larger, A laminate characterized in that the in-plane distribution of the film thickness of the gallium oxide film is ±3.1% or more and 11.7% or less.

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