Film Forming Apparatus and Film Forming Method

Abstract

To provide a film deposition apparatus to which a mist CVD method having an excellent film deposition rate is applicable.SOLUTION: A film deposition apparatus 401 includes: a mist generation part 201 for generating a mist by changing a raw material solution 102a into a mist; a pipe that is connected to the mist generating part 201 and transports a carrier gas containing the mist; at least one or more pipes for transporting an addition liquid with a component of one or more types of gases for mixing with the carrier gas containing the mist; a pipe that is connected to a film deposition part 420 and transports a mixture mist fluid in which the carrier gas containing the mist and the addition fluid are mixed; a connection member for connecting the pipe for transporting the carrier gas including the mist, the pipe for transporting the addition fluid and the pipe for transporting the mixture mist fluid; and a film deposition part 420 for performing a deposition on a substrate by heat-treating the mist. An angle between the pipe for transporting the addition fluid and the pipe for transporting the mixture mist fluid, which are connected by the connection member, is 120 degree or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a film forming apparatus and a film forming method for forming a film on a substrate using a mist-like raw material.

Background Art

[0002] Conventionally, high-vacuum film forming apparatuses capable of realizing non-equilibrium states such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), and sputtering have been developed, and it has become possible to fabricate oxide semiconductors that were impossible to fabricate by conventional melting methods and the like.

[0003] In addition, a mist chemical vapor deposition method (Mist Chemical Vapor Deposition: Mist CVD; hereinafter also referred to as the "mist CVD method") for crystal growth on a substrate using an atomized mist-like raw material has been developed, and it has become possible to fabricate gallium oxide (α-Ga2O3) having a corundum structure. α-Ga2O3 is expected to be applied to next-generation switching elements that can achieve high breakdown voltage, low loss, and high heat resistance as a semiconductor with a large bandgap.

[0004] 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 mist CVD apparatus of a tubular furnace, which is different 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 installed above the mist generator, and further, a susceptor is a rotating stage provided on a hot plate.

[0005] Fig. 13 shows an enlarged view of the connection part 301h between the pipe for transporting the carrier gas containing mist and the pipe for transporting the dilution gas in Fig. 1 of Patent Document 6. As shown in Fig. 13, in Patent Document 6, for each of the pipe 302 for transporting the carrier gas containing mist and the pipe 304 for transporting the mixed mist fluid, a pipe 303 for transporting the addition fluid, which is the dilution gas, is connected at a right angle. The mist produced in the raw material supply system is transported by the carrier gas, and the dilution gas (addition fluid) having the vector B of the flow of the addition fluid orthogonal to the vector A of the flow of the carrier gas containing the mist is mixed. A mist CVD apparatus is described in which the vector C of the flow of the mixed mist fluid is parallel to the vector A of the flow of the carrier gas containing the mist. By using the dilution gas, the linear velocity of the mixed mist fluid is adjusted independently of the transport amount of the mist, and the in-plane film thickness distribution is improved by using supply means for supplying such a mixed mist fluid in opposite directions.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0007] Unlike other CVD methods, the mist CVD method can form a film at a relatively low temperature and can also produce a crystal structure of a metastable phase such as the corundum structure of α-Ga2O3.

[0008] However, the present inventors have found a new problem that during the transport of the mist, the mist collides with the piping and condenses due to the additive fluid which is a diluent gas, and / or the additive fluid flows backward into the piping of the carrier gas containing the mist, resulting in a decrease in the transport efficiency of the mist and a decrease in the film formation rate. This problem was particularly prominent when increasing the flow rate, that is, when forming a film on a large-area substrate or a plurality of substrates that require a large amount of gas. In response to such a problem, Patent Document 7 describes a mist CVD apparatus that extends the life of the mist and improves the film formation rate by heating the mist transport section. However, even when this method is used, the decrease in the film formation rate has not been completely eliminated.

[0009] The present invention has been made to solve the above problems, and an object thereof is to provide a film forming apparatus to which a mist CVD method excellent in film formation rate is applicable, and a film forming method excellent in film formation rate.

Means for Solving the Problems

[0010] The present invention has been made to achieve the above object, and is a film forming apparatus comprising at least a mist forming section that atomizes a raw material solution to generate a mist, a piping that is connected to the mist forming section and transports a carrier gas containing the mist, at least one piping that transports an additive fluid mainly composed of one or more kinds of gases and is mixed with the carrier gas containing the mist, a piping that is connected to the film forming section and transports a mixed mist fluid in which the carrier gas containing the mist and the additive fluid are mixed, a connection member that connects the piping that transports the carrier gas containing the mist, the piping that transports the additive fluid, and the piping that transports the mixed mist fluid, and a film forming section that heat-treats the mist to form a film on a substrate, and provides a film forming apparatus in which an angle formed by the piping that transports the additive fluid and the piping that transports the mixed mist fluid, which are connected by the connection member, is 120 degrees or more.

[0011] According to such a film forming apparatus, with a simple apparatus configuration, it is possible to suppress the backflow of the fluid for addition to the pipe that conveys the carrier gas containing mist. Further, it is possible to suppress the reduction of mist due to the collision against the connection portion wall surface, and to improve the film forming rate.

[0012] At this time, the angle formed by the pipe that conveys the fluid for addition and the pipe that conveys the mixed mist fluid can be set to 180 degrees.

[0013] Thereby, the backflow of the fluid for addition to the pipe that conveys the carrier gas containing mist can be further suppressed. Further, it is possible to further suppress the reduction of mist due to the collision against the pipe wall surface of the connection portion, and to further improve the film forming rate.

[0014] At this time, the linear velocity of the fluid for addition can be set to be 1 to 100 times the linear velocity of the carrier gas containing mist.

[0015] Thereby, it is possible to further suppress the reduction of mist due to the collision against the connection portion wall surface. Further, due to the ejector effect, the carrier gas containing low-speed mist is attracted by the high-speed fluid for addition at the connection portion, so that it is possible to convey the mist more stably, and to further improve the film forming rate.

[0016] Further, the present invention provides a film forming apparatus including at least: a mist generating unit configured to atomize a raw material solution to generate mist; a pipe connected to the mist generating unit for transporting a carrier gas containing the mist; at least one pipe for transporting an additive fluid mainly composed of one or more kinds of gases and mixed with the carrier gas containing the mist; a pipe connected to the film forming unit for transporting a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid; a connecting member connecting the pipe for transporting the carrier gas containing the mist, the pipe for transporting the additive fluid, and the pipe for transporting the mixed mist fluid; and a film forming unit configured to heat-treat the mist to form a film on a substrate. An angle formed by the pipe for transporting the additive fluid and the pipe for transporting the mixed mist fluid, which are connected by the connecting member, is 100 degrees or more, and a linear velocity of the additive fluid at the connecting portion is equal to or higher than a linear velocity of the carrier gas containing the mist.

[0017] According to such a film forming apparatus, even when a large flow rate of gas is flowing, backflow of the additive fluid into the pipe for transporting the carrier gas containing the mist can be suppressed with a simple apparatus configuration. Further, a decrease in mist due to collision with the connecting portion wall surface can be suppressed, and the film forming rate can be improved.

[0018] At this time, the angle formed by the pipe for transporting the additive fluid and the pipe for transporting the mixed mist fluid can be 120 degrees or more.

[0019] Thereby, backflow of the additive fluid into the pipe for transporting the carrier gas containing the mist can be further suppressed. Further, a decrease in mist due to collision with the pipe wall surface of the connecting portion can be further suppressed, and the film forming rate can be further improved.

[0020] At this time, the linear velocity of the additive fluid at the connecting portion can be 10 times or more the linear velocity of the carrier gas containing the mist.

[0021] As a result, it is possible to further suppress the reduction of mist due to the collision against the connection part wall surface. Also, due to the ejector effect, the high-speed additive fluid draws in the carrier gas containing low-speed mist at the connection part, enabling the mist to be transported more stably and making it possible to further improve the film formation rate.

[0022] At this time, it is possible to use a film forming apparatus in which the cross-sectional area of the portion of the connection member that connects to the pipe for transporting the additive fluid is less than or equal to the cross-sectional area of the portion of the connection member that connects to the pipe for transporting the carrier gas containing the mist.

[0023] As a result, the flow rate of the additive fluid can at least increase the linear velocity of the additive fluid, increasing the degree of freedom of the linear velocity of the mist, which is industrially advantageous.

[0024] At this time, it is possible to use a film forming apparatus in which the flow rate of the carrier gas is 8 L / min or more.

[0025] As a result, it is possible to form a film at a higher film formation rate even when forming a film on a large-area substrate that requires a large flow rate.

[0026] At this time, it is possible to use a film forming apparatus that can process a substrate with an area of 10 cm 2 or more.

[0027] As a result, it is possible to form a film over a large area at a faster film formation rate.

[0028] The present invention also provides a film forming method, which includes a step of atomizing a raw material solution in an atomizing section to generate mist, a step of supplying a carrier gas to the atomizing section to convey the carrier gas containing the mist from the atomizing section, a step of mixing the carrier gas containing the mist with at least one kind of additive fluid mainly composed of one or more kinds of gases to form a mixed mist fluid, a step of conveying the mixed mist fluid to a film forming section, and a step of performing heat treatment on the mist in the mixed mist fluid in the film forming section to form a film on a substrate. In the step of forming the mixed mist fluid, a film forming method is provided in which the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is 60 degrees or less.

[0029] According to such a film forming method, backflow of the additive fluid into the pipe for conveying the carrier gas containing the mist can be suppressed, and a decrease in mist due to collision with the connection part wall surface can be suppressed. Therefore, the conveyance efficiency of the mist can be greatly improved, and the film forming speed can be increased.

[0030] At this time, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid can be 0 degrees.

[0031] Thereby, backflow of the additive fluid into the pipe for conveying the carrier gas containing the mist can be further suppressed, the conveyance efficiency of the mist can be further improved, and the film forming speed can be further increased.

[0032] At this time, the linear velocity of the additive fluid can be 1 to 100 times the linear velocity of the carrier gas containing the mist.

[0033] Thereby, it is possible to further improve the conveyance efficiency of the mist. Also, due to the ejector effect, the carrier gas flow containing low-speed mist is attracted by the high-speed additive fluid at the connection part, so that the mist can be conveyed more stably, and the film forming speed can be further increased.

[0034] The present invention also provides a film forming method, which includes a step of atomizing a raw material solution in an atomizing section to generate mist, a step of supplying a carrier gas to the atomizing section to convey a carrier gas containing the mist from the atomizing section, a step of mixing the carrier gas containing the mist with at least one additive fluid mainly composed of one or more types of gases to form a mixed mist fluid, a step of conveying the mixed mist fluid to a film forming section, and a step of performing heat treatment on the mist in the mixed mist fluid in the film forming section to form a film on a substrate. In the step of forming the mixed mist fluid, an angle formed by a vector of the flow of the additive fluid and a vector of the flow of the mixed mist fluid is set to 80 degrees or less, and a linear velocity of the additive fluid at the connection section is set to be equal to or higher than a linear velocity of the carrier gas containing the mist, thereby providing a film forming method.

[0035] According to such a film forming method, backflow of the additive fluid into the pipe for conveying the carrier gas containing the mist can be suppressed, and a decrease in mist due to collision with the connection section wall surface can be suppressed. Therefore, the conveyance efficiency of the mist can be greatly improved, and the film forming speed can be increased.

[0036] At this time, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid can be set to 60 degrees or less.

[0037] Thereby, backflow of the additive fluid into the pipe for conveying the carrier gas containing the mist can be further suppressed, the conveyance efficiency of the mist can be further improved, and the film forming speed can be further increased.

[0038] At this time, the linear velocity of the additive fluid at the connection section can be set to be 10 times or more the linear velocity of the carrier gas containing the mist.

[0039] This makes it possible to further improve the transport efficiency of the mist. Also, due to the ejector effect, a carrier gas flow containing a high-speed additive fluid and a low-speed mist is drawn to the connection part, enabling the mist to be transported more stably and improving the film formation rate further.

[0040] At this time, the flow rate of the carrier gas can be set to 8 L / min or more.

[0041] This enables film formation at a higher film formation rate even on a large-area substrate that requires a large flow rate.

[0042] At this time, a substrate with an area of 10 cm 2 or more can be used.

[0043] This makes it possible to form a film over a large area at a faster film formation rate.

Advantages of the Invention

[0044] As described above, according to the film forming apparatus of the present invention, with a simple apparatus configuration, backflow of the additive fluid into the pipe for transporting the carrier gas containing the mist can be suppressed, reduction of the mist due to collision with the connection part wall surface can be suppressed, the transport efficiency of the mist is good, and it is possible to greatly improve the film formation rate. Also, according to the film forming method of the present invention, with a simple method, it is possible to greatly improve the transport efficiency of the mist and the film formation rate.

Brief Description of the Drawings

[0045]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0046] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0047] As described above, there has been a demand for a film forming apparatus to which a mist CVD method excellent in film forming speed can be applied, and a film forming method excellent in film forming speed.

[0048] As a result of intensive studies on the above problems, the inventor of the present invention has found that a film forming apparatus includes an atomizing unit that atomizes a raw material solution to generate mist, a pipe that is connected to the atomizing unit and conveys a carrier gas containing the mist, at least one pipe that conveys an additive fluid mainly composed of one or more kinds of gases and is mixed with the carrier gas containing the mist, a pipe that is connected to a film forming unit and conveys a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid, a connection member that connects the pipe that conveys the carrier gas containing the mist, the pipe that conveys the additive fluid, and the pipe that conveys the mixed mist fluid, and a film forming unit that heat-treats the mist to form a film on a substrate. By using a film forming apparatus in which the angle formed by the pipe that conveys the additive fluid and the pipe that conveys the mixed mist fluid, which are connected by the connection member, is 120 degrees or more, a mist CVD method excellent in film forming speed can be applied, and thus the present invention has been completed.

[0049] The inventor of the present invention has also found that a film forming apparatus includes an atomizing unit that atomizes a raw material solution to generate mist, a pipe that is connected to the atomizing unit and conveys a carrier gas containing the mist, at least one pipe that conveys an additive fluid mainly composed of one or more kinds of gases and is mixed with the carrier gas containing the mist, a pipe that is connected to a film forming unit and conveys a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid, a connection member that connects the pipe that conveys the carrier gas containing the mist, the pipe that conveys the additive fluid, and the pipe that conveys the mixed mist fluid, and a film forming unit that heat-treats the mist to form a film on a substrate. By using a film forming apparatus in which the angle formed by the pipe that conveys the additive fluid and the pipe that conveys the mixed mist fluid, which are connected by the connection member, is 100 degrees or more, and the linear velocity of the additive fluid at the connection part is equal to or higher than the linear velocity of the carrier gas containing the mist, a mist CVD method excellent in film forming speed can be applied, and thus the present invention has been completed.

[0050] Also, a film-forming method includes a step of atomizing a raw material solution in an atomizing section to generate mist, a step of supplying a carrier gas to the atomizing section to convey the carrier gas containing the mist from the atomizing section, a step of mixing the carrier gas containing the mist and at least one additive fluid mainly composed of one or more gases to form a mixed mist fluid, a step of conveying the mixed mist fluid to a film-forming section, and a step of performing heat treatment on the mist in the mixed mist fluid in the film-forming section to form a film on a substrate. In the step of forming the mixed mist fluid, by setting the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid to 60 degrees or less, a film-forming method excellent in film-forming speed has been found, and the present invention has been completed.

[0051] Furthermore, a film-forming method includes a step of atomizing a raw material solution in an atomizing section to generate mist, a step of supplying a carrier gas to the atomizing section to convey the carrier gas containing the mist from the atomizing section, a step of mixing the carrier gas containing the mist and at least one additive fluid mainly composed of one or more gases to form a mixed mist fluid, a step of conveying the mixed mist fluid to a film-forming section, and a step of performing heat treatment on the mist in the mixed mist fluid in the film-forming section to form a film on a substrate. In the step of forming the mixed mist fluid, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is set to 80 degrees or less, and the linear velocity of the additive fluid at the connecting section is set to be equal to or higher than the linear velocity of the carrier gas containing the mist. By this film-forming method, a film-forming method excellent in film-forming speed has been found, and the present invention has been completed.

[0052] Hereinafter, it will be described with reference to the drawings.

[0053] Here, the mist referred to in the present invention means a general term for fine particles of a liquid dispersed in a gas, and includes those called fog, droplets, and the like.

[0054] The film forming apparatus according to the present invention includes at least a mist generating unit that atomizes a raw material solution to generate mist, a pipe connected to the mist generating unit for transporting a carrier gas containing the mist, at least one pipe for transporting an additive fluid mainly composed of one or more kinds of gases to be mixed with the carrier gas containing the mist, a pipe connected to the film forming unit for transporting a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid, a connecting member for connecting the pipe for transporting the carrier gas containing the mist, the pipe for transporting the additive fluid, and the pipe for transporting the mixed mist fluid, and a film forming unit for heat-treating the mist to form a film on a substrate. Hereinafter, the components of the film forming apparatus according to the present invention will be described in detail. Note that descriptions of matters common to each drawing may be omitted as appropriate.

[0055] (Film forming apparatus) Fig. 1 shows an example of a film forming apparatus 401 according to the present invention. The film forming apparatus 401 includes a carrier gas supply unit 120, an additive fluid supply unit 130, a mist generating unit 201, a film forming unit 420 for heat-treating the mist to form a film on a substrate 403, a mixed mist fluid transport unit 107, and a connection unit 301 for connecting the additive fluid supply unit 130, the mist generating unit 201, and the mixed mist fluid transport unit 107. Further, the film forming apparatus 401 may be provided with a control unit (not shown) for controlling the whole or a part of the film forming apparatus 401, so that its operation is controlled. Hereinafter, the description will be divided into the film forming unit 420 and a raw material supply system 101 (see Fig. 2) on the upstream side of the film forming unit 420 as viewed from the flow of the raw material.

[0056] (Raw material supply system) FIG. 2 shows an example of a raw material supply system 101 according to the present invention. The raw material supply system 101 includes an atomization unit 201 that atomizes a raw material solution 102a to generate a mist, a carrier gas supply unit 120 that supplies a carrier gas for transporting the mist, an additive fluid supply unit 130 that supplies an additive fluid to be mixed with the carrier gas containing the mist, a mixed mist fluid transport unit 107 that transports a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid, and a connection unit 301 that connects the atomization unit 201, the additive fluid supply unit 130, and the mixed mist fluid transport unit 107. The carrier gas supply unit 120 is connected to the additive fluid supply unit 130 and the mixed mist fluid transport unit 107 via the atomization unit 201.

[0057] (Atomization unit) In the atomization unit 201, a raw material solution 102a is prepared, and the raw material solution 102a is atomized to generate a mist. The atomization means is not particularly limited as long as it can atomize the raw material solution 102a, and may be a known atomization means, but it is preferable to use an atomization means by ultrasonic vibration. This is because mist can be generated more stably.

[0058] An example of such an atomization unit 201 will be described with reference to FIG. 3 as well. For example, the atomization unit 201 may include a mist generation source 102 that stores the raw material solution 102a, a container 103 that contains a medium capable of transmitting ultrasonic vibration, such as water 103a, and an ultrasonic vibrator 104 attached to the bottom surface of the container 103. Specifically, the mist generation source 102 storing the raw material solution 102a is stored in the container 103 containing the water 103a using a support (not shown). An ultrasonic vibrator 104 is provided at the bottom of the container 103, and the ultrasonic vibrator 104 and an oscillator 202 are connected. When the oscillator 202 is operated, the ultrasonic vibrator 104 vibrates, ultrasonic waves propagate into the mist generation source 102 through the water 103a, and the raw material solution 102a is configured to be atomized.

[0059] (Carrier gas supply unit) As shown in FIGS. 1 and 2, the carrier gas supply unit 120 has a carrier gas source 105a that supplies a carrier gas. At this time, it may be provided with a flow rate control valve 105b for adjusting the flow rate of the carrier gas sent out from the carrier gas source 105a.

[0060] The type of the carrier gas is not particularly limited and can be appropriately selected according to the film-forming material. For example, oxygen, ozone, an inert gas such as nitrogen or argon, or a reducing gas such as hydrogen gas or forming gas can be mentioned. Also, the type of the 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 (for example, diluted 10 times) may be further used as the second carrier gas, and air can also be used.

[0061] Also, the supply location of the carrier gas may be not only one location but also two or more locations. 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 (about 100 mm), it is preferably 1 to 80 L / min, and more preferably 2 to 20 L / min.

[0062] In addition, the flow rate in the present invention is a measured value at 20°C. When measured at other temperatures or when different types of flow rates (such as mass flow rate) are measured, it can be converted into the volume flow rate at 20°C using the gas state equation.

[0063] (Additive fluid supply unit) As shown in FIGS. 1 and 2, the additive fluid supply unit 130 has an additive fluid source 106a that supplies an additive fluid. At this time, it may be provided with a flow rate control valve 106b for adjusting the flow rate of the gas in the additive fluid sent out from the additive fluid source 106a.

[0064] The fluid for addition mainly consists of one or more types of gases. The type of gas is not particularly limited and can be appropriately selected according to the film-forming material. For example, oxygen, ozone, inert gases such as nitrogen and argon, or reducing gases such as hydrogen gas and forming gas can be mentioned. Also, if one or more types of gases are the main components of the fluid for addition, it may contain mist.

[0065] Also, the supply location of the fluid for addition may be not only one location but also two or more locations. The flow rate of the gas in the fluid for addition is not particularly limited. When forming a film on a substrate with a diameter of 4 inches (about 100 mm), it is preferably 1 to 80 L / min, and more preferably 4 to 40 L / min.

[0066] (Connection part) An example of the connection part 301 will be described with reference to FIG. 4 as well. The connection part 301 is connected to the atomization part 201 and includes a pipe 302 for transporting a carrier gas containing mist, a pipe 303 for transporting the fluid for addition that is mixed with the carrier gas containing mist in the fluid for addition supply part 130, a pipe 304 for transporting a mixed mist fluid obtained by mixing the carrier gas containing mist and the fluid for addition in the mixed mist fluid transport part 107 connected to the film-forming part 402, and a connection member 305 for connecting these pipes.

[0067] The materials of these pipes and connection members include, but are not limited to, glass, quartz, vinyl chloride, chlorinated polyether, acrylic resin, fluororesin (perfluoroalkoxy alkane, polytetrafluoroethylene, polychlorotrifluoroethylene), polyethylene, polypropylene, polystyrene, polyurethane, etc.

[0068] In the film forming apparatus according to the present invention, the connection portion 301 is connected by the connection member 305 such that the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid, which are connected by the connection member 305, is 120 degrees or more. In particular, it is more preferable to set it to 180 degrees. For example, the connection portion 301a in FIG. 5 is an example where the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is 120 degrees, and the connection portion 301 in FIG. 4 is an example where θ is 180 degrees. When the connection portion 301 has the above structure, since the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is large (120 degrees or more), the backflow of the carrier gas containing the mist of the additive fluid into the pipe 302 for transporting is suppressed, and also, no matter how the carrier gas containing the mist is connected, the reduction of the mist due to the collision with the connection portion wall surface can be suppressed. Regarding the flow vectors (A to C in the figure), they will be described later.

[0069] If the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is 120 degrees or more, the direction (connection angle) of the pipe 302 for transporting the carrier gas containing the mist, such as the connection member 305b of the connection portion 301b in FIG. 6 or the connection member 305c of the connection portion 301c in FIG. 7, is not limited.

[0070] If the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is 120 degrees or more, a second pipe 303d for transporting the additive fluid may be connected, such as the connection member 305d of the connection portion 301d in FIG. 8. In this case, the angles formed by the pipe 303 for transporting the additive fluid and the second pipe 303d for transporting the additive fluid with the pipe 304 for transporting the mixed mist fluid may be different. Also, as shown in FIG. 9, the thickness and cross-sectional area of the portions connecting the respective pipes may be different.

[0071] Also, at this time, it is preferable that the linear velocity of the fluid for addition is 1 to 100 times the linear velocity of the carrier gas containing mist. To achieve this, the flow rate of each fluid may be controlled by the above-described control unit, or it is also possible by adjusting the flow rate of the fluid for addition and the cross-sectional area of the pipe, and the flow rate of the carrier gas containing mist and the cross-sectional area of the pipe.

[0072] Thereby, a decrease in mist due to collision with the connection part wall surface can be further suppressed, and also, due to the ejector effect, the carrier gas containing low-speed mist is attracted by the high-speed fluid for addition at the connection part, so that the mist can be transported more stably, and the film formation speed can be further improved.

[0073] In the film forming apparatus according to the present invention, further, the connection part 301 is connected by the connection member 305 such that the angle θ formed by the pipe 303 for transporting the fluid for addition and the pipe 304 for transporting the mixed mist fluid, which are connected by the connection member 305, is 100 degrees or more, and the linear velocity of the fluid for addition in the connection part 301 is made equal to or higher than the linear velocity of the carrier gas containing mist. At this time, in particular, it is preferably 120 degrees or more, and more preferably 180 degrees. For example, the connection member 305a of the connection part 301a in FIG. 5 is an example where the angle θ formed by the pipe 303 for transporting the fluid for addition and the pipe 304 for transporting the mixed mist fluid is 120 degrees, and FIG. 4 is an example where θ is 180 degrees. When the connection part 301 has the above structure, since the angle θ formed by the pipe 303 for transporting the fluid for addition and the pipe 304 for transporting the mixed mist fluid is large (100 degrees or more), backflow of the carrier gas containing mist of the fluid for addition into the pipe 302 for transportation is suppressed, and also, no matter how the carrier gas containing mist is connected, a decrease in mist due to collision with the connection part wall surface can be suppressed.

[0074] Also, at this time, the linear velocity of the fluid for addition is not particularly limited as long as the linear velocity of the fluid for addition at the connection part 301 is equal to or higher than the linear velocity of the carrier gas containing mist. If it is 10 times or more, the effects of the present invention are more remarkably exhibited. Also, the upper limit of the ratio of the linear velocities is not particularly limited. The faster the velocity of the fluid for addition, the more remarkably the effect of suppressing the decrease in the film formation rate due to the configuration of the present invention is exhibited. To achieve this, the flow rate of each fluid may be controlled by the above-described control unit, or it is also possible by adjusting the flow rate of the fluid for addition and the cross-sectional area of the pipe, and the flow rate of the carrier gas containing mist and the cross-sectional area of the pipe. At the connection part 301, the cross-sectional area of the portion connecting the pipe 303 that conveys the fluid for addition of the connection member 305 may be made equal to or smaller than the cross-sectional area of the portion connecting the pipe 302 that conveys the carrier gas containing mist of the connection member 305. For example, as in the connection member 305e of the connection part 301e in FIG. 9, by making the portion connecting the pipe 303 that conveys the fluid for addition of the connection member 305e thinner (reducing the cross-sectional area) than the portion connecting to other pipes, the linear velocity can be increased with a small amount of the fluid for addition, the degree of freedom of the linear velocity of the mist increases, which is industrially advantageous. Also, if the total amount of the gas supplied to the film formation part is large, there is a problem that the heat of the film formation part is taken away by the gas and the crystallinity of the film to be formed decreases. Therefore, by adopting the configuration as in FIG. 9, it is possible to increase the conveyance efficiency of the mist and the film formation rate while suppressing the exhaust heat by the gas.

[0075] Also, the linear velocity can be calculated by dividing the volume flow rate at 20°C by the cross-sectional area. When measured at other temperatures or when different types of flow rates (mass flow rate, etc.) are measured, it can be converted to the volume flow rate at 20°C using the equation of state of the gas.

[0076] Thereby, it is possible to further suppress the reduction of the mist due to the collision with the connection part wall surface, and also, due to the ejector effect, the carrier gas containing the low-speed mist is attracted to the high-speed fluid for addition at the connection part, so that it becomes possible to convey the mist more stably and improve the film formation rate.

[0077] (Film formation part) In the film forming section 420, the mist is heated to cause a thermal reaction, and a film is formed on part or all of the surface of the substrate 403. The film forming section 420 includes, for example, a film forming chamber 402 in which the substrate 403 is installed, and may include a hot plate 404 for heating the substrate 403. The hot plate 404 may be provided outside the film forming chamber 402 as shown in FIG. 1, or may be provided inside the film forming chamber 402. Further, the film forming chamber 402 may be provided with an exhaust port 405 for exhaust gas at a position that does not affect the supply of the mist to the substrate 403.

[0078] Also, in the present invention, the substrate 403 may be installed on the upper surface of the film forming chamber 402 to be face down, or the substrate 403 may be installed on the bottom surface of the film forming chamber 402 to be face up.

[0079] Furthermore, the film forming apparatus is more preferably capable of processing a substrate having an area of 10 cm 2 or more. When the substrate is a circular wafer, for example, it is preferably capable of processing a wafer having a diameter of 2 inches (about 50 mm) or more. With such a film forming apparatus, it is possible to form a film over a large area at a higher film forming speed.

[0080] (Raw material solution) The raw material solution 102a is not particularly limited as long as it contains a material that can be atomized, and may be an inorganic material or an organic material. Metals or metal compounds are preferably used, and those containing one or more metals selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, and cobalt can be used.

[0081] The raw material solution 102a is not particularly limited as long as it can atomize the above metal. However, as the raw material solution 102a, a solution or dispersion of the metal in the form of a complex or salt in an organic solvent or water can be preferably used. Examples of the form of the complex include acetylacetonate complex, carbonyl complex, ammine complex, hydride complex, etc. Examples of the form of the salt include metal chloride salt, metal bromide salt, metal iodide salt, etc. In addition, a solution obtained by dissolving the above metal in hydrobromic acid, hydrochloric acid, hydroiodic acid, etc. can also be used as an aqueous salt solution.

[0082] Moreover, additives such as hydrohalic acid and oxidizing agent may be mixed into the raw material solution 102a. Examples of the hydrohalic acid include hydrobromic acid, hydrochloric acid, hydroiodic acid, etc. Among them, hydrobromic acid or hydroiodic acid is preferable. Examples of the oxidizing agent include peroxides such as hydrogen peroxide (H2O2), sodium peroxide (Na2O2), barium peroxide (BaO2), benzoyl peroxide (C6H5CO)2O2, hypochlorous acid (HClO), perchloric acid, nitric acid, ozone water, organic peroxides such as peracetic acid and nitrobenzene, etc.

[0083] Furthermore, the raw material solution 102a may contain a dopant. The dopant is not particularly limited. For example, n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium or niobium, or p-type dopants such as copper, silver, tin, iridium, rhodium, etc. can be mentioned. The concentration of the dopant can be, for example, about 1×10 16 / cm 3 ~1×10 22 / cm 3 and may be, or may be at a low concentration of about 1×10 17 / cm 3 or less, or may be at a high concentration of about 1×10 20 / cm 3 or more.

[0084] (Substrate) The substrate 403 is not particularly limited as long as it can form a film and support the film. The material of the substrate 403 is also not particularly limited, and known substrates can be used, which may be organic compounds or inorganic compounds. For example, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, gold, silicon, sapphire, quartz, glass, gallium oxide, lithium tantalate, etc. can be mentioned, but it is not limited thereto. The thickness of the substrate is not particularly limited, but preferably 10 to 2000 μm, more preferably 50 to 800 μm. The area of the substrate is not particularly limited, but 10 cm 2 or more is preferable. When the substrate is a circular wafer, for example, those with a diameter of 2 inches (about 50 mm) or more are preferable. This is because a film can be formed on a large area at a high film formation rate.

[0085] Also, the film formation may be directly performed 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, they are Al2O3, Ti2O3, V2O3, Cr2O3, Fe2O3, Ga2O3, Rh2O3, In2O3, Ir2O3. Also, when two elements selected from the above metal elements are A and B, (A x B 1-x )2O3 (0 < x < 1) binary metal oxides represented by, or when three elements selected from the above metal elements are A, B, and C, (A x B y C 1-x-y )2O3 (0 < x < 1, 0 < y < 1) ternary metal oxides represented by can be used.

[0086] (Film Formation Method) The film formation method according to the present invention includes a step of atomizing a raw material solution 102a in an atomizing unit 201 to generate a mist, a step of supplying a carrier gas to the atomizing unit 201 and transporting the carrier gas containing the mist from the atomizing unit 201, a step of mixing the carrier gas containing the mist with at least one additive fluid mainly composed of one or more kinds of gases to form a mixed mist fluid, a step of transporting the mixed mist fluid to a film forming unit 420, and a step of performing heat treatment on the mist in the mixed mist fluid in the film forming unit 420 to form a film on a substrate 403. And in the step of forming the above mixed mist fluid, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is 60 degrees or less.

[0087] Hereinafter, an example of the film formation method according to the present invention will be described with reference to FIGS. 1 and 2. One embodiment of the film formation method according to the present invention is that when transporting a mist generated by atomizing or dropletizing a raw material solution in a raw material supply system to a substrate in a film forming unit with a carrier gas, an additive fluid is mixed to form a mixed mist fluid, and the mist is thermally reacted on the substrate to form a film.

[0088] First, the raw material solution 102a is accommodated in the mist generation source 102, the substrate 403 is installed directly on the hot plate 404 or via the wall of the film forming chamber 402, and the hot plate 404 is operated. Next, the flow rate regulating valve 105b is opened to supply the carrier gas from the carrier gas source 105a into the film forming chamber 402. After sufficiently replacing the atmosphere of the film forming chamber 402 with the carrier gas, the flow rate of the carrier gas and the flow rate of the gas in the additive fluid are adjusted by the flow rate regulating valves 105b and 106b, respectively.

[0089] Next, in the atomizing unit 201, the ultrasonic vibrator 104 is vibrated, and the vibration is propagated to the raw material solution 102a through the water 103a, thereby atomizing the raw material solution 102a to generate a mist (step of generating a mist).

[0090] Next, the mist is transported to the connection part 301 by the carrier gas supplied to the mist generation part 201 (step of transporting the carrier gas containing the mist from the mist generation part).

[0091] Then, in the connection part 301, the carrier gas containing the mist and at least one kind of additive fluid mainly composed of one or more kinds of gases are mixed to form a mixed mist fluid (step of forming the mixed mist fluid).

[0092] At this time, as shown in FIGS. 4 and 5, in the step of forming the mixed mist fluid, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is set to 60 degrees or less. When the angle formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is θ (degrees), the angles of the above vectors B and C correspond to 180 - θ (degrees). That is, as described for the connection part 301 above, when the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid are connected so that the angle θ formed therebetween is 120 degrees or more, and when transporting the additive fluid and the mixed mist fluid, expressed as "the angle formed by the vector B of the flow of the additive fluid and the vector of the flow of the mixed mist fluid", it is 60 degrees or less. In the connection part 301, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid can be 60 degrees, or can also be 0 degrees. In this way, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is made 60 degrees or less. In particular, 0 degrees is more preferable.

[0093] As described above, FIG. 5 shows an example where the angle θ formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is 120 degrees. However, when gas is flowed through such a connection part 301, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is 60 degrees. In the example shown in FIG. 4 (θ = 180 degrees), the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is 0 degrees.

[0094] If the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is 60 degrees or less, the vector A (direction) of the flow of the carrier gas containing the mist is not limited (see FIGS. 6 and 7).

[0095] Also, at this time, it is preferable that the linear velocity of the additive fluid is 1 to 100 times the linear velocity of the carrier gas containing the mist. For example, according to the cross-sectional area of each pipe, the flow rate of the additive fluid and the flow rate of the carrier gas containing the mist can be adjusted.

[0096] Thereby, a further reduction in mist due to collision with the connection part wall surface can be suppressed, and due to the ejector effect, the carrier gas containing low-speed mist is attracted to the high-speed additive fluid in the connection part 301, so that the mist can be stably transported, and the film formation speed can be further improved.

[0097] Furthermore, through the mixed mist fluid conveyance section 107, the mixed mist fluid is conveyed to the substrate 403 in the film formation chamber 402 (step of conveying the mixed mist fluid to the film formation section). By thus conveying the mixed mist fluid to the film formation section, it becomes possible to increase the conveyance efficiency of the mist to the film formation section 420.

[0098] Furthermore, the mist in the mixed mist fluid undergoes a thermal reaction due to the heat of the hot plate 404 in the film formation chamber 402 and forms a film on the substrate 403. By supplying the mist in this way, the mist introduced into the film formation chamber 402 forms a film on the substrate 403 at a high film formation speed (step of forming a film). Note that the gas in the film formation chamber 402 may be exhausted to the outside from an exhaust port 405 provided above the substrate 403.

[0099] For the thermal reaction, it is sufficient that the mist reacts by heating, and the reaction conditions and the like are not particularly limited. The raw materials can be appropriately set according to the film-forming material. For example, the heating temperature can be 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.

[0100] The thermal reaction may be carried out under any atmosphere of vacuum, non-oxygen atmosphere, reducing gas atmosphere, air atmosphere and oxygen atmosphere, and may be appropriately set according to the film-forming material. Further, the reaction pressure may be carried out under any condition of atmospheric pressure, increased pressure or reduced pressure. However, in the case of film formation under atmospheric pressure, the apparatus configuration can be simplified, which is preferable.

[0101] The film-forming method according to the present invention is also characterized in that, in the step of forming the above mixed mist fluid, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is 80 degrees or less, and the linear velocity of the additive fluid at the connection portion 301 is equal to or higher than the linear velocity of the carrier gas containing the mist.

[0102] At this time, as shown in FIGS. 4 and 5, in the step of forming the mixed mist fluid, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is 80 degrees or less. When the angle formed by the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid is θ (degrees), the angles of the vectors B and C are corresponding to 180 - θ (degrees). That is, as described for the connection portion 301 above, when the pipe 303 for transporting the additive fluid and the pipe 304 for transporting the mixed mist fluid are connected so that the angle θ formed therebetween is 100 degrees or more, in the case of transporting the additive fluid and the mixed mist fluid, when expressed as "the angle formed by the vector B of the flow of the additive fluid and the vector of the flow of the mixed mist fluid", it is 80 degrees or less. At the connection portion 301, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid can be 60 degrees, or can also be 0 degrees. In this way, the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is made 80 degrees or less. In particular, 60 degrees or less is preferable, and 0 degrees is more preferable.

[0103] If the angle formed by the vector B of the flow of the additive fluid and the vector C of the flow of the mixed mist fluid is 80 degrees or less, the vector A (direction) of the flow of the carrier gas containing the mist is not limited (see FIGS. 6 and 7).

[0104] Also, at this time, the linear velocity of the fluid for addition is not particularly limited as long as the linear velocity of the fluid for addition at the connection part 301 is equal to or higher than the linear velocity of the carrier gas containing mist. If it is 10 times or more, the effects of the present invention are more significantly exhibited. Also, the upper limit of the ratio of the linear velocities is not particularly limited. The faster the velocity of the fluid for addition, the more significantly the effect of suppressing the decrease in the film formation rate due to the configuration of the present invention is exhibited. For example, according to the cross-sectional area of each pipe, the flow rate of the fluid for addition and the flow rate of the carrier gas containing mist can be adjusted.

[0105] Thereby, a further reduction in mist due to collision with the connection part wall surface can be suppressed, and also, due to the ejector effect, the carrier gas containing slow mist is attracted by the high-speed fluid for addition at the connection part 301, so that it becomes possible to stably convey the mist and further improve the film formation rate.

[0106] In the present invention, annealing treatment may be performed after film formation. The temperature of the annealing treatment is not particularly limited, but is preferably 600°C or lower, and more preferably 550°C or lower. This is to prevent damage to the crystallinity of the film. The treatment time of the annealing treatment is not particularly limited, but is preferably 10 seconds to 10 hours, and more preferably 10 seconds to 1 hour.

Examples

[0107] Hereinafter, the present invention will be specifically described with reference to examples, but this does not limit the present invention.

[0108] (Example 1) First, while referring to FIG. 1, the film forming apparatus 401 used in Example 1 will be described. As the film forming apparatus 401, a carrier gas source 105a for supplying a carrier gas, a flow rate regulating valve 105b for regulating the flow rate of the carrier gas sent out from the carrier gas source 105a, an additive fluid source 106a for supplying an additive fluid, a flow rate regulating valve 106b for regulating the flow rate of the gas in the additive fluid sent out from the additive fluid source 106a, a mist generating source 102 that houses the raw material solution 102a, a container 103 that houses water 103a, an ultrasonic vibrator 104 attached to the bottom surface of the container 103, a film forming chamber 402, a pipe, a connection part 301, and a mixed mist fluid conveyance part 107 that connect the mist generating source 102 to the film forming chamber 402, and a hot plate 404 provided outside the film forming chamber 402 were used.

[0109] In Example 1, as shown in FIG. 4, for the connection part 301, a T-shaped connection member 305 was used, and a pipe 303 for conveying an additive fluid made of perfluoroalkoxy alkane (PFA) and a pipe 304 for conveying a mixed mist fluid were connected to the connection member 305 such that the angle formed by these pipes was 180 degrees, and a pipe 302 for conveying a carrier gas containing a mist made of PFA was connected to the connection member 305 so as to form a 90-degree angle with respect to each of these pipes.

[0110] First, a raw material solution was prepared. An aqueous solution of 0.05 mol / L gallium iodide was adjusted, and further a 48% hydroiodic acid solution was contained so that the volume ratio was 10%, and this was used as the raw material solution 102a.

[0111] The raw material solution 102a obtained as described above was housed in the mist generating source 102. Next, a c-plane sapphire substrate with a diameter of 4 inches (about 100 mm) was placed on the hot plate 404 in the film forming chamber 402 as the substrate 403, and the hot plate 404 was operated to raise the temperature to 450°C.

[0112] Next, the flow control valve 105b was opened to supply carrier gas from the carrier gas source 105a into the film formation chamber 402. After sufficiently replacing the atmosphere in the film formation chamber 402 with the carrier gas, the flow rate of the carrier gas and the flow rate of the additive fluid were adjusted to 8 L / min and 40 L / min, respectively. Nitrogen was used as the carrier gas and the additive fluid.

[0113] Next, the ultrasonic vibrator 104 was vibrated at 2.4 MHz, and the vibration was propagated to the raw material solution 102a through the water 103a to atomize the raw material solution 102a and generate mist. This mist was transported to the connection part 301 by the carrier gas, mixed with the additive fluid in the connection part 301, and introduced into the film formation chamber 402 through the mixed mist fluid transport part 107. Then, under the conditions of atmospheric pressure and 450 °C, the mist was thermally reacted in the film formation chamber 402 to form a thin film of gallium oxide (α-Ga2O3) having a corundum structure on the substrate 403. The film formation time was 30 minutes.

[0114] The reduction amount per unit time of the raw material solution 102a in the mist generation source 102 was defined as the time-averaged mist flow rate, and the time-averaged mist flow rate was measured and film formation was performed.

[0115] Regarding the thin film formed on the substrate 403, the measurement points were 17 points in the plane on the substrate 403, and the film thickness was measured using a step gauge, and the average film thickness was calculated from each value.

[0116] The time-averaged mist flow rate was 3.2 g / min, the average film thickness was 660 nm, and the film formation rate obtained by dividing the average film thickness by the film formation time was 1320 nm / h.

[0117] (Example 2) As shown in Fig. 5, a Y-shaped pipe with θ = 120 degrees was used as the connecting member 305a. Film formation and evaluation were carried out in the same manner as in Example 1, except that the angles formed by the pipe 303 for conveying the additive fluid and the pipe 304 for conveying the mixed mist fluid, the angle formed by the pipe 303 for conveying the additive fluid and the pipe 302 for conveying the carrier gas containing mist, and the angle formed by the pipe 304 for conveying the mixed mist fluid and the pipe 302 for conveying the carrier gas containing mist were all 120 degrees.

[0118] The time-averaged mist flow rate was 3.0 g / min, the average film thickness was 590 nm, and the film formation rate was 1180 nm / h.

[0119] (Comparative Example 1) As shown in Fig. 13, a T-shaped connecting member 305h with θ = 90 degrees was used. The pipe 302 for conveying the carrier gas containing mist made of PFA and the pipe 304 for conveying the mixed mist fluid were connected to the connecting member 305h such that the angle formed by these pipes was 180 degrees. The pipe 303 for conveying the additive fluid made of PFA was connected to these pipes at an angle of 90 degrees to each of them. Film formation and evaluation were carried out in the same manner as in Example 1.

[0120] The time-averaged mist flow rate was 1.7 g / min, the average film thickness was 230 nm, and the film formation rate was 460 nm / h.

[0121] (Example 3) Film formation and evaluation were carried out in the same manner as in Example 1, except that the flow rate of the carrier gas and the flow rate of the additive fluid were adjusted to 20 L / min and 5 L / min, respectively. The time-averaged mist flow rate was 4.6 g / min, the average film thickness was 1140 nm, and the film formation rate was 2280 nm / h.

[0122] (Comparative Example 2) Film formation and evaluation were carried out in the same manner as in Comparative Example 1, except that the flow rate of the carrier gas and the flow rate of the additive fluid were adjusted to 20 L / min and 5 L / min, respectively. The time-averaged mist flow rate was 2.7 g / min, the average film thickness was 540 nm, and the film formation rate was 1080 nm / h.

[0123] (Reference Example) Film formation and evaluation were carried out in the same manner as in Example 1, except that the flow rate of the carrier gas and the flow rate of the fluid for addition were adjusted to 2 L / min and 50 L / min, respectively, and the film formation time was set to 120 minutes. The time-averaged mist flow rate was 0.7 g / min, the average film thickness was 280 nm, and the film formation rate was 140 nm / h.

[0124] (Comparative Example 3) Film formation and evaluation were carried out in the same manner as in Comparative Example 1, except that the flow rate of the carrier gas and the flow rate of the fluid for addition were adjusted to 2 L / min and 50 L / min, respectively, and the film formation time was set to 120 minutes. The time-averaged mist flow rate was 0.1 g / min, the average film thickness was 60 nm, and the film formation rate was 30 nm / h.

[0125] The results of Examples 1 to 3, the reference example, and Comparative Examples 1 to 3 were summarized in Table 1.

[0126]

Table 1

[0127] From the comparison between Examples 1 to 3, the reference example, and Comparative Examples 1 to 3, it was found that by setting the angle formed by the pipe for transporting the fluid for addition and the pipe for transporting the mixed mist fluid to 120 degrees or more, the time-averaged mist flow rate was greatly improved, and the film formation rate was also greatly improved.

[0128] (Example 5) In Example 5, the same apparatus as the film forming apparatus 401 used in Example 1 was used. The differences from Example 1 are described below.

[0129] In Example 5, as shown in FIG. 9, for the connection part 301, a T-shaped connection member 305e is used to connect a pipe 303 for transporting an additive fluid made of perfluoroalkoxy alkane (PFA) and a pipe 304 for transporting a mixed mist fluid to the connection member 305e such that the angle formed by these pipes is 180 degrees, and a pipe 302 for transporting a carrier gas containing a mist made of PFA is connected to the connection member 305e so as to form a 90-degree angle with each of these pipes. At this time, the cross-sectional area S B of the portion of the connection member 305e that connects to the pipe 303 for transporting the additive fluid A and the cross-sectional area S A of the portion of the connection member 305e that connects to the pipe 302 for transporting the carrier gas containing the mist B The ratio was defined as α (=S

[0130] / S

[0131] ), and α was 20. Also, at this time, the inner diameter of the portion of the connection member 305e that connects to the pipe 303 for transporting the additive fluid was 0.4 cm, and the inner diameter of the portion of the connection member 305e that connects to the pipe 302 for transporting the carrier gas containing the mist was 3.6 cm.

[0132] First, a raw material solution was prepared. An aqueous solution of 0.05 mol / L gallium iodide was adjusted, and further a 48% hydroiodic acid solution was contained so that the volume ratio was 10%, and this was used as the raw material solution 102a.

[0133] Next, the ultrasonic vibrator 104 was vibrated at 2.4 MHz, and the vibration was propagated to the raw material solution 102a through the water 103a, thereby atomizing the raw material solution 102a to generate mist. This mist was conveyed to the connection part 301 by a carrier gas, mixed with the additive fluid in the connection part 301, and introduced into the film forming chamber 402 through the mixed mist fluid conveyance part 107. Then, under the conditions of atmospheric pressure and 450 °C, the mist was thermally reacted in the film forming chamber 402 to form a thin film of gallium oxide (α-Ga2O3) having a corundum structure on the substrate 403. The film forming time was set to 60 minutes.

[0134] The reduction amount per unit time of the raw material solution 102a in the mist generation source 102 was defined as the time-averaged mist flow rate, and the time-averaged mist flow rate was measured and film formation was performed.

[0135] Regarding the thin film formed on the substrate 403, the measurement points were set to 17 points in the plane on the substrate 403, and the film thickness was measured using a step gauge, and the average film thickness was calculated from each value. The film formation rate was calculated by dividing the average film thickness by the film formation time.

[0136] (Examples 6 to 8) The same procedure as in Example 5 was carried out except that the flow rates of the additive fluid were set to 10, 20, and 40 L / min.

[0137] (Comparative Example 4) Using a T-shaped connecting member 305h with θ = 90 degrees as shown in FIG. 13, a pipe 302 for conveying a carrier gas containing mist made of PFA and a pipe 304 for conveying a mixed mist fluid were connected to the connecting member 305h so that the angle formed by these pipes was 180 degrees, and a pipe 303 for conveying an additive fluid made of PFA was connected to these pipes so as to form 90 degrees with respect to each of them. Film formation and evaluation were carried out in the same manner as in Example 5 except for this.

[0138] (Comparative Examples 5 to 7) The same procedure as in Comparative Example 4 was carried out except that the flow rates of the additive fluid were set to 10, 20, and 40 L / min.

[0139] (Example 9) The cross-sectional area S of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305, by changing the shape of the connection member 305 B and the cross-sectional area S of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 A Except that the ratio α was made 1 and the flow rate of the fluid for addition was made 8 L / min, film formation was performed in the same manner as in Example 5. At this time, the inner diameter of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305 was 1.8 cm, and the inner diameter of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 was 1.8 cm.

[0140] (Comparative Example 8) The cross-sectional area S of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305, by changing the shape of the connection member 305 B and the cross-sectional area S of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 A Except that the ratio α was made 1 and the flow rate of the fluid for addition was made 8 L / min, film formation was performed in the same manner as in Comparative Example 4. At this time, the inner diameter of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305 was 1.8 cm, and the inner diameter of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 was 1.8 cm.

[0141] (Example 10) The cross-sectional area S of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305, by changing the shape of the connection member 305 B and the cross-sectional area S of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 A Except that the ratio α was made 50 and the flow rate of the fluid for addition was made 24 L / min, the same procedure as in Example 5 was carried out. At this time, the inner diameter of the portion connecting the pipe 303 that conveys the fluid for addition to the connection member 305 was 0.8 cm, and the inner diameter of the portion connecting the pipe 302 that conveys the carrier gas containing the mist of the connection member 305 was 5.6 cm.

[0142] (Comparative Example 9) Changing the shape of the connecting member 305, the cross-sectional area S of the portion connecting to the pipe 303 that conveys the fluid for addition to the connecting member 305 B and the cross-sectional area S of the portion connecting to the pipe 302 that conveys the carrier gas containing the mist of the connecting member 305 A Except that the ratio α was set to 50 and the flow rate of the fluid for addition was set to 24 L / min, the procedure was the same as in Comparative Example 4. Also, at this time, the inner diameter of the portion connecting to the pipe 303 that conveys the fluid for addition to the connecting member 305 was 0.8 cm, and the inner diameter of the portion connecting to the pipe 302 that conveys the carrier gas containing the mist of the connecting member 305 was 5.6 cm.

[0143] (Example 11) As shown in FIG. 5, a Y-shaped pipe with θ = 120 degrees was used as the connecting member 305a. The film formation and evaluation were performed in the same manner as in Example 5, except that the angle formed by the pipe 303 that conveys the fluid for addition, the pipe 304 that conveys the mixed mist fluid, the angle formed by the pipe 303 that conveys the fluid for addition and the pipe 302 that conveys the carrier gas containing the mist, and the angle formed by the pipe 304 that conveys the mixed mist fluid and the pipe 302 that conveys the carrier gas containing the mist were all 120 degrees.

[0144] (Example 12) The procedure was the same as in Example 11, except that the flow rate of the fluid for addition was set to 40 L / min.

[0145] (Example 13) As shown in FIG. 10, a Y-shaped pipe with θ = 100 degrees was used as the connecting member 305f. The film formation and evaluation were performed in the same manner as in Example 5, except that the angle formed by the pipe 303 that conveys the fluid for addition and the pipe 304 that conveys the mixed mist fluid was 100 degrees, and the angle formed by the pipe 303 that conveys the fluid for addition and the pipe 302 that conveys the carrier gas containing the mist, and the angle formed by the pipe 304 that conveys the mixed mist fluid and the pipe 302 that conveys the carrier gas containing the mist were all 130 degrees.

[0146] (Example 14) The procedure was the same as in Example 13, except that the flow rate of the fluid for addition was set to 10 L / min.

[0147] The results of Examples 5 to 14 and Comparative Examples 4 to 9 are summarized in Table 2. Note that the piping angle represents the angle formed by the pipe for conveying the additive fluid and the pipe for conveying the mixed mist fluid, and the linear velocity ratio represents the value obtained by dividing the linear velocity of the additive fluid by the linear velocity of the carrier gas. Also, FIGS. 11 and 12 show diagrams in which the time-average mist flow rate and the film formation rate are plotted against the linear velocity ratio, respectively.

[0148] [Table 2]

[0149] (Example 15) The fact that a sapphire substrate with a diameter of 6 inches (150 mm) was used, the cross-sectional area S of the portion connecting the pipe 303 for conveying the additive fluid of the connection member 305 B and the cross-sectional area S of the portion connecting the pipe 302 for conveying the carrier gas containing mist of the connection member 305 A with a ratio α of 1, and film formation was carried out in the same manner as in Example 5 except that the flow rate of the carrier gas and the flow rate of the additive fluid were both 20 L / min. At this time, the linear velocity ratio was 1, the inner diameter of the portion connecting the pipe 303 for conveying the additive fluid of the connection member 305 was 2.6 cm, and the inner diameter of the portion connecting the connection member 305 and the pipe 302 for conveying the carrier gas containing mist was 2.6 cm. Also, the time-average mist flow rate was 4.65 g / min, and the film formation rate was 1.42 μm / hr.

[0150] (Example 16) The fact that a sapphire substrate with a diameter of 6 inches (150 mm) was used, the cross-sectional area S of the portion connecting the pipe 303 for conveying the additive fluid of the connection member 305 B and the cross-sectional area S of the portion connecting the pipe 302 for conveying the carrier gas containing mist of the connection member 305 AThe ratio α was set to 1, and the flow rates of both the carrier gas and the fluid for addition were set to 20 L / min. Film formation was carried out in the same manner as in Example 11 except for this. At this time, the linear velocity ratio was 1, the inner diameter of the portion connecting the pipe 303 for transporting the fluid for addition of the connection member 305 was 2.6 cm, and the inner diameter of the portion connecting the connection member 305 and the pipe 302 for transporting the carrier gas containing mist was 2.6 cm. Also, the time-averaged mist flow rate was 4.25 g / min, and the film formation rate was 1.26 μm / hr.

[0151] (Example 17) A sapphire substrate with a diameter of 6 inches (150 mm) was used, and the cross-sectional area S of the portion connecting the pipe 303 for transporting the fluid for addition of the connection member 305 B and the cross-sectional area S of the portion connecting the connection member 305 and the pipe 302 for transporting the carrier gas containing mist A The ratio α was set to 1, and the flow rates of both the carrier gas and the fluid for addition were set to 20 L / min. Film formation was carried out in the same manner as in Example 13 except for this. At this time, the linear velocity ratio was 1, the inner diameter of the portion connecting the pipe 303 for transporting the fluid for addition of the connection member 305 was 2.6 cm, and the inner diameter of the portion connecting the connection member 305 and the pipe 302 for transporting the carrier gas containing mist was 2.6 cm. Also, the time-averaged mist flow rate was 4.04 g / min, and the film formation rate was 1.06 μm / hr.

[0152] (Comparative Example 10) A sapphire substrate with a diameter of 6 inches (150 mm) was used, and the cross-sectional area S of the portion connecting the pipe 303 for transporting the fluid for addition of the connection member 305 B and the cross-sectional area S of the portion connecting the connection member 305 and the pipe 302 for transporting the carrier gas containing mist AThe ratio α was set to 1, and the flow rates of both the carrier gas and the fluid for addition were set to 20 L / min. Film formation was performed in the same manner as in Comparative Example 4 except for this. At this time, the linear velocity ratio was 1, the inner diameter of the portion connecting the pipe 303 that conveys the fluid for addition of the connecting member 305 was 2.6 cm, and the inner diameter of the portion connecting the connecting member 305 and the pipe 302 that conveys the carrier gas containing mist was 2.6 cm. Also, the time-averaged mist flow rate was 1.81 g / min, and the film formation rate was 0.43 μm / hr.

[0153] From the comparison between Examples 5 to 14 and Comparative Examples 4 to 9, and between Examples 15 to 17 and Comparative Example 10, it was found that by setting the angle formed by the pipe that conveys the fluid for addition and the pipe that conveys the mixed mist fluid to 100 degrees or more, and setting the linear velocity of the fluid for addition to be equal to or higher than the linear velocity of the carrier gas, the time-averaged mist flow rate is greatly improved, and the film formation rate is also greatly improved.

[0154] Note that the present invention is not limited to the above-described embodiments. The above-described embodiments are illustrative, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Claims

1. A film forming apparatus, comprising: an atomizing section that atomizes a raw material solution to generate mist; a pipe connected to the atomizing section for transporting a carrier gas containing the mist; at least one pipe for transporting an additive fluid mainly composed of one or more types of gases to be mixed with the carrier gas containing the mist; a pipe connected to a film forming section for transporting a mixed mist fluid obtained by mixing the carrier gas containing the mist and the additive fluid; a connecting member that connects the pipe for transporting the carrier gas containing the mist, the pipe for transporting the additive fluid, and the pipe for transporting the mixed mist fluid; a film forming section that heat-treats the mist to form a film on a substrate; a control section; and at least including: wherein an angle formed by the pipe for transporting the additive fluid and the pipe for transporting the mixed mist fluid, which are connected by the connecting member, is 100 degrees or more; the control section controls the flow rate of the carrier gas and the flow rate of the additive fluid so that the film forming rate is 1.1 μm / hr or more. The film forming apparatus is characterized by this.

2. The film forming apparatus according to claim 1, wherein an angle formed by the pipe for transporting the additive fluid and the pipe for transporting the mixed mist fluid is 120 degrees or more.

3. The film forming apparatus according to claim 1 or claim 2, wherein the control section makes a linear velocity of the additive fluid at a connection portion where the pipe for transporting the carrier gas containing the mist, the pipe for transporting the additive fluid, and the pipe for transporting the mixed mist fluid are connected by the connecting member be 10 times or more the linear velocity of the carrier gas containing the mist.

4. The film forming apparatus according to any one of claims 1 to 3, wherein a cross-sectional area of a portion of the connecting member connected to the pipe for transporting the additive fluid is equal to or less than a cross-sectional area of a portion of the connecting member connected to the pipe for transporting the carrier gas containing the mist.

5. The film forming apparatus according to any one of claims 1 to 4, wherein the control section makes the flow rate of the carrier gas be 8 L / min or more.

6. The substrate has an area of 10 cm ２ The film forming apparatus according to any one of claims 1 to 5, characterized in that it is capable of processing a substrate having an area of 10 cm or more.

7. A film forming method, comprising: a step of atomizing a raw material solution in an atomizing section to generate mist; a step of supplying a carrier gas to the atomizing section and transporting a carrier gas containing the mist from the atomizing section; A step of mixing a carrier gas containing the mist and at least one additive fluid mainly composed of one or more gases to form a mixed mist fluid; A step of transporting the mixed mist fluid to a film forming section; A step of performing heat treatment on the mist in the mixed mist fluid in the film forming section to form a film on a substrate including; In the step of forming the mixed mist fluid, the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is set to 80 degrees or less; A film forming method characterized by controlling the flow rate of the carrier gas and the flow rate of the additive fluid so that the film forming rate is 1.1 μm / hr or more.

8. A film forming method, comprising: A step of atomizing a raw material solution in an atomizing section to generate a mist; A step of supplying a carrier gas to the atomizing section and transporting a carrier gas containing the mist from the atomizing section; A step of mixing a carrier gas containing the mist and at least one additive fluid mainly composed of one or more gases to form a mixed mist fluid; A step of transporting the mixed mist fluid to a film forming section; A step of performing heat treatment on the mist in the mixed mist fluid in the film forming section to form a film on a substrate including; In the step of forming the mixed mist fluid, setting the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid, and controlling the flow rate of the carrier gas and the flow rate of the additive fluid so that the film forming rate is 1.1 μm / hr or more. A film forming method characterized by that.

9. The film forming method according to claim 7 or claim 8, characterized in that the angle formed by the vector of the flow of the additive fluid and the vector of the flow of the mixed mist fluid is 60 degrees or less.

10. The linear velocity of the additive fluid in the connection part where a pipe for transporting the carrier gas containing the mist, a pipe for transporting the additive fluid, and a pipe for transporting the mixed mist fluid are connected by a connection member is 10 times or more the linear velocity of the carrier gas containing the mist. The film forming method according to any one of claims 7 to 9, characterized by that.

11. The film forming method according to any one of claims 7 to 10, characterized in that the flow rate of the carrier gas is 8 L / min or more.

12. The substrate has an area of 10 cm ２ The film forming method according to any one of claims 7 to 11, characterized in that the above is used.

Images