TWI535883B - Film forming apparatus and film forming method - Google Patents

Description

Film forming device and film forming method

This invention relates to useful new film forming apparatus and film forming methods for atomized chemical vapor deposition.

In the prior art, high-vacuum film formation in a non-equilibrium state can be realized by pulsed laser deposition (PLD), molecular beam epitaxy (MBE), sputtering, and the like. The device makes it possible to manufacture an oxide semiconductor which cannot be obtained by a melt method or the like. Among them, an atomized chemical vapor deposition method (Mist Chemical Vapor Deposition), which uses an atomized raw material to grow crystals on a substrate, has been studied to produce corundum (hereinafter referred to as a mist CVD method). Coralum structure of gallium oxide (α-Ga ₂ O ₃ ) is possible. In the case of α-Ga ₂ O ₃ , a semiconductor having a large bandgap is expected to be used in a next-generation switching element capable of achieving high withstand voltage, low loss, and high heat resistance.

Regarding the fog CVD method, Patent Document 1 discloses a tubular furnace type mist CVD apparatus. Patent Document 2 discloses a Fine Channel type mist CVD apparatus. Patent Document 3 discloses a linear source type mist CVD apparatus. Patent Document 4 A mist CVD apparatus in which a tubular furnace is opened differs from a mist CVD apparatus described in Patent Document 1 in a carrier gas introduced into a mist generator. Further, Patent Document 5 discloses a mist CVD apparatus as a rotary stage in which a substrate is provided above a mist generator, and a susceptor is further provided on a hot plate.

However, unlike the other methods, the fog CVD method can produce a metastable phase crystal structure such as a corundum structure of α-gallium oxide without requiring high temperature; and the fog evaporation layer covers the substrate according to the Leidenfrost effect described in Non-Patent Document 1. On the surface, droplets of mist do not directly contact the film to make crystal growth necessary, and control thereof is not easy, and it is difficult to obtain a homogeneous crystal film. Further, in the fog CVD method, the mist particles are not uniform, or the deposition of the mist in the supply tube is continued until the substrate is applied, and these problems cause problems such as a low film formation rate.

[Background Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 1-257337

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-307238

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2012-46772

[Patent Document 4] Japanese Patent No. 5397794

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2014-63973

[Non-patent literature]

[Non-Patent Document 1] B.S. Gottfried., et al., "Film Boiling of Spheroidal Droplets. Leidenfrost Phenomenon", Ind. Eng. Chem. Fundamen., 1966, 5(4), pp 561~568

An object of the present invention is to provide a film forming apparatus and a film forming method which are excellent in film formation rate and which can be used by a fog CVD method.

The inventors of the present invention conducted intensive studies in order to achieve the above object, and as a result, the mist or the droplets were swirled back to the film formation portion, and the mist CVD apparatus having the unit (Means) was successfully developed. When a film is formed by a fog CVD method using such a mist CVD apparatus, it is surprising that a film formation rate is excellent, and a uniform film thickness distribution can be formed in a large area. It has also been found that the above-mentioned problems in the prior art can be solved at once by such a device.

Further, the inventors of the present invention have completed the present invention by repeated studies after obtaining the above conclusions.

That is, the invention related to the present invention is as follows.

[1] A film forming apparatus, characterized in that the apparatus is provided with atomization for atomizing or dropletizing a raw material solution. The dropletization part, with the carrier gas will be in the atomization. The mist or droplet generated by the droplet formation portion is transported to the transport portion of the substrate, and the mist or the liquid droplet is heat-treated to form a film on the substrate. a film portion; the film forming portion includes means (Means) for rotating the mist or the droplets to generate a swirling flow.

[2] A film forming apparatus as described in the above [1], wherein the swirling flow is inward flowing.

[3] The film forming apparatus described in the above [1] or [2], wherein the film forming portion is cylindrical or substantially cylindrical, and the side of the film forming portion is provided on the side of the film forming portion. The mist or the inlet of the droplet.

[4] The film forming apparatus described in the above [3], wherein in the apparatus, the mist or the exhaust of the droplets is provided at a distance from the substrate at a distance from the inlet of the film forming portion. mouth.

[5] The film forming apparatus according to any one of [1] to [4] further comprising an exhaust fan.

[6] The film forming apparatus according to any one of [1] to [5] wherein the film forming portion has a hot plate.

[7] The film forming apparatus according to any one of [1] to [6] above, wherein the film forming apparatus is atomized. The droplet formation unit is provided with an ultrasonic vibrator.

[8] A film forming method, characterized in that a mist or a droplet obtained by atomizing or dropletizing a raw material solution by a carrier gas is transported to a substrate provided in a film forming chamber, and then the mist or liquid is applied to the substrate. The droplet is thermally reacted to form a film. In the film forming method, the mist or the droplet is rotated back in the film forming chamber to cause a swirling back.

[9] The film forming method described in the above [8], in which the swirling back flows inward.

[10] The film forming method according to [8] or [9] above, wherein the film forming portion is cylindrical or substantially cylindrical, and the mist is provided on a side surface of the film forming portion. Or the inlet of the droplet.

[11] The film forming method according to the above 10, wherein in the method, the mist or the discharge port of the liquid droplet is provided at a distance from the inlet of the film forming chamber.

[12] The film forming method according to [11] above, wherein in the method, an exhaust fan is further provided to perform the exhaust.

[13] The film forming method according to any one of [8] to [12] wherein, in the method, ultrasonic vibration is used The atomization or dropletization is performed.

In the film forming apparatus and the film forming method of the present invention, a fog CVD method can be used, and the film forming rate is excellent.

1‧‧‧ film forming device

2a‧‧‧ Carrier gas source

2b‧‧‧Diluted carrier gas source

3a‧‧‧Flow regulating valve

3b‧‧‧Flow regulating valve

4‧‧‧The source of fog

4a‧‧‧ raw material solution

4b‧‧‧Fog

4c‧‧‧Exhaust

5‧‧‧ Container

5a‧‧‧Water

6‧‧‧ Ultrasonic vibrator

6a‧‧‧electrode

6b‧‧‧piezoelectric unit

6c‧‧‧electrode

6d‧‧‧ Elastomers

6e‧‧‧Support

7‧‧‧filming room

8‧‧‧Hot board

9‧‧‧Supply tube

10‧‧‧Substrate

11‧‧‧Exhaust fan

16‧‧‧Oscillator

17‧‧‧Exhaust pipe

19‧‧‧Mist CVD device

20‧‧‧Substrate

21‧‧‧Base

22a‧‧‧carrier gas supply unit

22b‧‧‧Diluted carrier gas supply unit

23a‧‧‧Flow regulating valve

23b‧‧‧Flow regulating valve

24‧‧‧The source of fog

24a‧‧‧ raw material solution

25‧‧‧ Container

25a‧‧‧Water

26‧‧‧ Ultrasonic vibrator

27‧‧‧Supply tube

28‧‧‧heater

29‧‧‧Exhaust port

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a film forming apparatus of the present invention.

Figure 2 is for the purpose of illustrating the atomization used in the present invention. One way of dropleting.

Figure 3 shows a mode of the ultrasonic vibrator of Figure 2.

Fig. 4 shows one mode of the film forming portion used in the present invention.

Fig. 5 is a view for explaining the measurement of the film thickness in the embodiment.

Fig. 6 is a schematic structural view of a film forming apparatus used in a comparative example.

Fig. 7 is a view for explaining the measurement of the thickness of the film used in the comparative example.

Fig. 8 is a schematic view showing the flow of mist or droplets on the substrate of the film forming chamber of Fig. 4. (a) is a schematic view showing a cross section of a cylinder forming film chamber as seen from above; (b) is a schematic view showing a cross section of a cylinder forming film chamber as seen from the side.

Fig. 9 shows the results of detection of XRD in the examples.

The film forming apparatus of the present invention is characterized in that the film forming apparatus is provided with atomization for atomizing or dropletizing a raw material solution. The dropletization part, with the carrier gas will be in the atomization. a mist or droplet generated by the dropletizing portion is transported to a transport portion of the substrate, and a film forming portion that forms a film on the substrate by heat-treating the mist or the droplet; the film forming portion is provided with the mist or the The droplets are swirled back to produce a unit that is swirled back.

The film forming apparatus of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited by the accompanying drawings.

Fig. 1 is a view showing an example of a film forming apparatus of the present invention. The film forming apparatus 1 includes a carrier gas source 2a for supplying a carrier gas, a flow rate adjusting valve 3a for adjusting a flow rate of a carrier gas sent from the carrier gas source 2a, a dilution carrier gas source 2b for supplying a dilution carrier gas, and an adjustment for dilution. a flow rate adjusting valve 3b for discharging a flow rate of the carrier gas to be supplied from the carrier gas source 2b, a mist generating source 4 for accommodating the raw material solution 4a, a container 5 for accommodating the water 5a, an ultrasonic vibrator 6 attached to the bottom surface of the container 5, a film forming chamber 7, A supply pipe 9 between the mist generating source 4 and the film forming chamber 7, a hot plate 8 provided in the film forming chamber 7, an exhaust pipe 17, and an exhaust fan 11 are connected. A substrate 10 is provided on the hot plate 8.

The film forming apparatus 1 of the present invention is provided with atomization for atomizing or dropletizing a raw material solution. Dropletization section. Figure 2 shows the atomization. One way of dropleting. The mist generating source 4 composed of a container containing the raw material solution 4a is housed in a container 5 in which the water 5a is accommodated in a support (not shown). An ultrasonic vibrator 6 is attached to the bottom of the container 5, and the ultrasonic vibrator 6 is connected to the oscillator 16. Further, when the oscillator 16 is operated, the ultrasonic vibrator 6 oscillates, and the ultrasonic wave is transmitted to the mist generating source 4 by the water 5a, and the raw material solution 4a is atomized or dropletized.

FIG. 3 is a mode of the ultrasonic vibrator 6 shown in FIG. 2. The ultrasonic vibrator of Fig. 3 is provided with a disk-shaped piezoelectric unit 6b in the cylindrical elastic body 6d on the support 6e, and electrodes 6a and 6c are provided on both surfaces of the piezoelectric unit 6b. When the oscillator is connected to the electrode and the oscillation frequency is changed, ultrasonic waves having a resonance frequency in the thickness direction of the piezoelectric oscillator and a radial resonance frequency are generated.

As described above, by atomization. The droplet formation unit adjusts the raw material solution, and atomizes or dropletizes the raw material solution to generate mist or droplets. The method (method) of atomization or droplet formation is not particularly limited as long as the raw material solution can be atomized or dropletized, and may be a known atomization method or droplet formation method, in the present invention. An atomization method or a dropletization method by ultrasonic vibration is preferred.

In the case of the transport unit, the mist or droplets are transported to the substrate using a carrier gas and a desired supply tube or the like. The type of the carrier gas is not particularly limited as long as it does not inhibit the object of the present invention, and suitable examples thereof include an inert gas such as oxygen, ozone, nitrogen or argon, or hydrogen or a forming gas. Reduction gas, etc. Further, the type of the carrier gas may be one type or two or more types. For example, it is also possible to use a first carrier gas and a diluent gas obtained by diluting (for example, diluting 10 times) the first carrier gas with another gas as the second carrier gas. Further, the supply of the carrier gas may be not only 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 square substrate having a side length of 30 mm, it is preferably 0.01 to 20 L/min, and more preferably 1 to 10 L/min.

In the film forming portion, the mist or the droplets are subjected to heat treatment to cause a thermal reaction to form a film on a part or all of the surface of the substrate. In the case of the thermal reaction, the mist or the droplets may be reacted by heating, and the reaction conditions and the like are not particularly limited as long as the object of the present invention is not inhibited. In the present step, the conditions and the like in the case of performing the thermal reaction are not particularly limited, and the heating temperature is usually in the range of 120 to 600 ° C, preferably in the range of 120 ° C to 350 ° C, and more preferably in the range of 130 ° C to 300 ° C. In addition, as far as the thermal reaction is concerned, as long as the object of the present invention is not hindered, it may be carried out under vacuum, a non-oxygen environment, a reducing gas atmosphere, and an oxygen atmosphere, and may be at atmospheric pressure. It is carried out under any of the following conditions, under pressure and under reduced pressure, and is preferably carried out under atmospheric pressure in the present invention.

Fig. 4 shows one mode of the film forming portion. The film forming chamber 7 of Fig. 4 is cylindrical and is disposed on the hot plate 8. The film forming chamber 7 and the mist generating source 4 are connected by the supply pipe 9, and the mist or droplets 4b generated by the mist generating source 4 flow into the film forming chamber 7 through the supply pipe 9 through the carrier gas, and are carried on the hot plate. A thermal reaction is performed on the upper substrate 10. As for the film forming chamber 7, there is an exhaust port at the center of the top surface (upper surface), and the mist or the exhaust port of the liquid droplet is disposed at a distance from the substrate at a distance from the feed port. Further, the film forming chamber 7 is connected to the exhaust pipe 17 from the exhaust port, and the mist, droplets or exhaust gas 4c after the heat reaction is transported to the exhaust pipe 17. In the present invention, a trap unit may be further provided, that is, a mist, a droplet or an exhaust gas after the heat reaction is subjected to a trap treatment. When the mist or the liquid droplet 4b is transported to the film forming chamber 7, as shown by the arrow in Fig. 4, the mist or the liquid droplet 4b flows out toward the substrate. At this point, an inward swirling recirculation occurs. Further, the mist or the droplet 4b is rotated while rotating on the substrate. Next, the mist, droplets or exhaust gas after the heat reaction flows to the exhaust port as indicated by an arrow in Fig. 4, and then transported to the exhaust pipe 19a.

The swirling flow may flow in either or both of the inward or outward directions, preferably flowing inwardly in the present invention. Fig. 8 is a schematic view for explaining the flow of mist or droplets on the substrate of the film forming chamber of Fig. 4. Fig. 8(a) is a cross section of the cylinder forming film chamber 7 as seen from above, in which the substrate 10 is disposed, and the flow of the mist or droplets is indicated by an arrow. In the film forming chamber of Fig. 4, a swirling recirculation occurs in the direction of the arrow in Fig. 8(a), and the mist or the droplets are swirled inward to flow toward the center of the substrate. Fig. 8 (b) is a schematic view showing a cross section of the cylindrical film forming chamber 7 as seen from the side, and the substrate 10 is placed in the film forming chamber 7. As shown by the arrow in Fig. 8(b), the mist or the droplet flows from the outside to the inside. Then, the mist or liquid droplets reaching the vicinity of the center of the substrate flow toward the upper exhaust port. Further, in the present invention, a substrate or the like may be provided on the top surface of the film forming chamber to face-down. Alternatively, as shown in FIG. 4, the base body may be provided on the bottom surface to be face-up. Further, the spinning recirculation generating unit is not particularly limited as long as it does not inhibit the object of the present invention, and a known unit can be used. For example, the film forming chamber has a cylindrical shape, and a substrate is disposed on the bottom surface or the top surface, and mist or liquid droplets are introduced from the side surface, and a discharge port is provided on a surface (preferably "at") symmetrical to the surface on which the substrate is disposed, so that the spiral is rotated. Units generated by the flow (means, Means), etc. In the case of a mist or a droplet, it is preferred that the mist or the droplet move along the inner wall surface of the film forming chamber and be introduced into the film forming chamber. Therefore, it is preferable that the introduction port of the mist or the liquid droplet substantially faces the tangential direction of the inner wall surface of the film forming chamber. However, when the mist or the liquid droplet is introduced into the deposition chamber toward the center of the film forming chamber in the radial direction, for example, by appropriately adjusting a known unit such as the carrier gas flow rate, the generation of the swirling flow is possible, so that the mist or the liquid droplet is introduced. The direction is not particularly limited. Further, the flow rate of the swirling reflux is not particularly limited as long as it does not inhibit the object of the present invention, and is preferably 10 to 100 cm/sec, and more preferably 20 to 70 cm/sec.

Hereinafter, the mode of use of the manufacturing apparatus of the present invention will be described with reference to Fig. 1 .

First, the raw material solution 4a is housed in the mist generating source 4, and the substrate 10 is placed on the hot plate 8, and the hot plate 8 is operated. Then, the flow rate adjusting valves (3a, 3b) are opened to supply the carrier gas from the carrier gas source (2a, 2b) to the film forming chamber 7, and the carrier gas is sufficiently replaced with the gas atmosphere (Atmosphere) of the film chamber 7, and then the load is adjusted separately. The flow rate of the gas and the flow rate of the carrier gas for dilution. Next, the ultrasonic vibrator 6 is oscillated, and the vibration is transmitted to the raw material solution 4a through the water 5a, whereby the raw material solution 4a is atomized or dropletized to generate a mist or a droplet 4b. Next, the mist or droplet 4b is introduced into the film forming chamber 7 by the carrier gas. An exhaust port is provided in the middle of the top surface of the film forming chamber 7, and is connected to the exhaust pipe 17. Further, the exhaust pipe 17 is connected to the exhaust fan 11, and is exhausted from the exhaust port by the exhaust gas or the like in the film forming chamber 7 of the exhaust fan 11. Further, a feed port for mist or droplets is provided on the side surface of the cylinder forming membrane chamber 7, and the mist or droplets introduced into the film forming chamber 7 are rotated to generate a swirling flow inward. The film can be formed on the substrate 10 by rotating the mist or liquid droplets in the film forming chamber 7 by heating the hot plate 8 while performing thermal reaction.

Further, the shape of the film forming chamber is not particularly limited as long as it does not inhibit the object of the present invention, and is preferably a cylindrical shape. The film forming chamber may be cylindrical or substantially cylindrical, prismatic (e.g., cubic, rectangular, pentagonal, hexagonal, or octagonal, etc.) or substantially prismatic, and may be preferred in the present invention. Shaped or substantially cylindrical.

Further, the substrate may be rotated at the time of film formation, and the direction of rotation is preferably opposite to the direction of the swirling.

(raw material solution)

As far as the raw material solution is concerned, if there is a material that can be atomized or dropletized, there is no Particularly limited, it may be an inorganic material or an organic material. In the present invention, a metal or a metal compound is preferable, and one or two or more metals selected from the group consisting of gallium, iron, indium, aluminum, vanadium, titanium, chromium, ruthenium, nickel, and cobalt are more preferable.

The raw material solution is not particularly limited as long as it can atomize or dropletize the above metal; the raw material solution in which the above metal is dissolved or dispersed in the form of a complex or a salt in an organic solvent or water, It can be used as appropriate. The form of the complex is, for example, an acetamylacetone complex, a carbonyl complex, an ammine complex, a hydrogenated complex or the like. The form of the salt is, for example, a metal chloride salt, a metal bromide salt, a metal iodide salt or the like.

Further, an additive such as a halogen acid or an oxidizing agent may be mixed in the raw material solution. The hydrohalic acid is, for example, hydrogen bromide, hydrochloric acid, hydrogen iodide or the like, preferably hydrogen bromide or hydrogen iodide. The oxidizing agent is, for example, hydrogen peroxide (H ₂ O ₂ ), sodium peroxide (Na ₂ O ₂ ), barium peroxide (BaO ₂ ), benzyl peroxide (C ₆ H ₅ CO) ₂ O ₂ such as peroxide, hypochlorous acid (HClO), perchloric acid, nitric acid, ozone water, peracetic acid or nitrobenzene and other organic peroxides.

The raw material solution may contain a dopant (Dopant). The dopant is not particularly limited as long as it does not inhibit the object of the present invention. As the dopant, there are an n-type dopant such as tin, antimony, bismuth, titanium, zirconium, vanadium or antimony, or a p-type dopant or the like. The concentration of the dopant may generally be about 1 × 10 ¹⁶ /cm ³ to 1 × 10 ²² /cm ³ . Further, the concentration of the dopant may be a low concentration of about 1 × 10 ¹⁷ /cm ³ or less. Further, the present invention may further contain a dopant having a high concentration of about 1 × 10 ²⁰ /cm ³ or more.

(matrix)

The substrate is not particularly limited if it can support the film. The material of the substrate is not particularly limited as long as it does not inhibit the object of the present invention, and may be a known substrate, and may be an organic compound or an inorganic compound. The shape of the base body may be any shape, and is effective for all shapes, such as a plate shape such as a flat plate or a circular plate, a fiber shape, a rod shape, a cylindrical shape, a prism shape, a cylindrical shape, a spiral shape, a spherical shape, and a ring shape. The present invention is preferably a substrate. The thickness of the substrate is not particularly limited, but is preferably 10 to 2000 μm, and more preferably 50 to 800 μm.

As described above, by using the film forming apparatus and the film forming method of the present invention, even if the film formation rate by the fog CVD method is good, a uniform film thickness distribution and large-area film formation are possible.

[Examples]

The embodiments of the present invention are described below, but the present invention is not limited thereto.

(Example 1) Manufacturing device

First, the film forming apparatus 1 used in the present embodiment will be described with reference to Fig. 1 . The film forming apparatus 1 includes a carrier gas source 2a for supplying a carrier gas, a flow rate adjusting valve 3a for adjusting a flow rate of a carrier gas sent from the carrier gas source 2a, a dilution carrier gas source 2b for supplying a dilution carrier gas, and an adjustment for dilution. Carrier gas source 2b, the flow rate adjusting valve 3b for discharging the flow rate of the carrier gas, the mist generating source 4 for accommodating the raw material solution 4a, the container 5 for accommodating the water 5a, the ultrasonic vibrator 6 attached to the bottom surface of the container 5, the film forming chamber 7, and the connection mist generation A supply pipe 9 between the source 4 and the film forming chamber 7, a hot plate 8 provided in the film forming chamber 7, an exhaust pipe 17, and an exhaust fan 11. A substrate 10 is provided on the hot plate 8.

2. Manufacture of raw material solution

An aqueous solution of 0.1 mol/L of gallium bromide was adjusted, and further, a 48% by volume hydrobromic acid solution having a volume ratio of 10% was further used as a raw material solution.

3. Film preparation

The raw material solution 4a obtained in the above 2. is stored in the mist generating source 4. Next, a 4-inch c-plane sapphire substrate is used as the substrate 10, and a c-plane sapphire substrate is placed on the hot plate 8, and the hot plate 8 is operated to raise the temperature in the film forming chamber 7 to 500 ° C. Next, the flow rate adjusting valves (3a, 3b) are opened, and a carrier gas is supplied from the carrier gas source (2a, 2b) to the film forming chamber 7, and the carrier gas is sufficiently replaced with the gas atmosphere of the film chamber 7, and then the flow rate of the carrier gas is adjusted. It was 5 L/min, and the flow rate of the dilution carrier gas was adjusted to 0.5 L/min. In addition, oxygen is used as a carrier gas.

4. Single layer film formation

Next, the ultrasonic vibrator 6 is oscillated at 2.4 MHz, and the oscillation is propagated to the raw material solution 4a by the water 5a, and the raw material solution 4a is atomized to generate the mist 4b. This mist 4b is introduced into the film forming chamber 7 by the carrier gas, and the mist is swirled back in the film forming chamber 7, and the swirling inflow which occurs inward as shown in Fig. 8 occurs. Next, under a condition of 560 ° C under atmospheric pressure, a mist which is swirled back in the film forming chamber 7 reacts. A film is formed on the substrate 10.

Further, the flow rate of the mist was 45.6 cm/sec, and the film formation time was 30 minutes.

5. Evaluation

The phase of the α-Ga ₂ O ₃ film obtained by the above 4. was identified. This identification was carried out by using an XRD diffraction apparatus for a film, and performing 2θ/ω scanning from an angle of 15 to 95 degrees, and the measurement was performed using a CuKα line. As a result, the obtained film was α-Ga ₂ O ₃ .

Further, regarding the respective measurement points (A1, A2, A3, A4, A5) of the film on the substrate 10 shown in Fig. 5, the film thickness was measured using a step profiler, and the average value was calculated from the values of the respective film thicknesses. The average film thickness was 3,960 nm. Next, the average film thickness was divided by the film formation time to obtain a film formation rate of 132 nm/min.

(Comparative example)

The film forming apparatus 19 for the comparative example will be described with reference to Fig. 6 . The mist CVD apparatus 19 includes a susceptor 21 for arranging the substrate 20, a supply unit 22a for supplying a carrier gas, a flow rate adjusting valve 23a for adjusting the flow rate of the carrier gas sent from the carrier gas supply unit 22a, and a supply dilution The carrier gas supply unit 22b for diluting the carrier gas, the flow rate adjustment valve 23b for adjusting the flow rate of the carrier gas sent from the dilution carrier gas supply unit 22b, the mist generation source 24 for storing the raw material solution 24a, and the container for accommodating the water 25a. 25. An ultrasonic vibrator 26 attached to the bottom surface of the container 25, a supply tube 27 composed of a quartz tube having an inner diameter of 40 mm, a heater 28 provided at a peripheral portion of the supply tube 27, and an exhaust port 29. The susceptor 21 is composed of quartz, and the surface on which the substrate 20 is placed is inclined from the horizontal plane. 45 degree. The supply pipe 27 and the susceptor 21 which are the film forming chambers are made of quartz, thereby suppressing impurities which are mixed in the film formed in the film formed on the substrate 20.

Film formation was carried out in the same manner as in Example 1 except that the film forming apparatus shown in Fig. 6 and a square c-plane sapphire substrate having a side length of 10 mm as the substrate 20 were used. With respect to the obtained film, the phase was identified by an XRD diffraction apparatus using a film as in the above-described examples. As a result, the obtained film was α-Ga ₂ O ₃ . Further, the film thickness was measured as in the above embodiment. In addition, the film thickness was measured at the respective measurement points (B1, B2, B3, B4, and B5) of the film on the substrate 20 as shown in FIG. The results are shown in Table 1 as a comparison.

(Example 2)

Film formation was carried out in the same manner as in Example 1 except that a square c-plane sapphire substrate having a side length of 10 mm was used as the substrate 10. The obtained film was identified by the XRD diffraction apparatus for the film in the same manner as in the above Comparative Example. As a result, the obtained film was α-Ga ₂ O ₃ . Further, the film thickness was measured as in the above comparative example. In addition, the film thickness was measured at the respective measurement points (B1, B2, B3, B4, and B5) of the film on the substrate 20 as shown in FIG. The results are shown in Table 1 as Example 2.

From the results of Table 1, the average film thickness, film formation rate, coefficient of variation, and in-plane uniformity were determined. The results are shown in Table 2. In addition, the average film thickness is the average of the film thicknesses at each measurement point. The film formation rate is a value obtained by dividing the average value of the film thickness at each measurement by the film formation time (minutes). The coefficient of variation is obtained by dividing the standard deviation of the film thickness by the average film thickness. In-plane uniformity is the difference between the mean and the maximum or minimum, the range of deviation expressed as a percentage.

Table 1 and Table 2 clearly show that in the examples, the film formation rate has an order of magnitude The difference in film formation quality such as film formation rate or in-plane uniformity is also remarkable. Therefore, the film forming apparatus and the film forming method of the present invention are excellent in uniformity in film formation rate or film thickness as compared with the conventional mist CVD apparatus.

(Example 3)

The mixture was adjusted to have a molar ratio of acetonitrile gallium chloride to acetam aluminum acetonate of 1:6, and hydrochloric acid was a 2% by volume aqueous solution as a raw material solution.

Using the obtained raw material solution, film formation was carried out in the same manner as in Example 1 except that the film formation temperature was 600 ° C, the flow rate of the carrier gas was 8 LPM, and the film formation time was 3 hours. In addition, the flow rate of the mist was 73.0 cm/sec. For the obtained film, the content ratio of aluminum was measured by X-ray. The XRD measurement results are shown in Fig. 9. According to the XRD measurement results, the obtained film was an AlGaO-based semiconductor film containing 62.8% of aluminum in a corundum structure which has been difficult to form so far. Further, for the AlGaO-based semiconductor film having a corundum structure, the film thickness was measured to be 720 nm.

It has been difficult to obtain a film having a thickness of 50 nm or more even if an AlGaO-based semiconductor film of a corundum structure is obtained. However, according to the present invention, an AlGaO-based semiconductor film having a corundum structure having a thickness of 700 nm or more can be obtained. Further, the film forming apparatus of the present invention is also very suitable for the fog CVD method; further, the film forming rate is particularly good.

[Industrial use possibilities]

The film forming apparatus and film forming method of the present invention can be used in all film forming fields and are industrially useful. In particular, when a film is formed by a fog CVD method and a film is formed, the film forming apparatus and the film forming method of the present invention can be suitably used.

1‧‧‧ film forming device

2a‧‧‧ Carrier gas source

2b‧‧‧Diluted carrier gas source

3a‧‧‧Flow regulating valve

3b‧‧‧Flow regulating valve

4‧‧‧The source of fog

4a‧‧‧ raw material solution

4b‧‧‧Fog

4c‧‧‧Exhaust

5‧‧‧ Container

5a‧‧‧Water

6‧‧‧ Ultrasonic vibrator

7‧‧‧filming room

8‧‧‧Hot board

9‧‧‧Supply tube

10‧‧‧Substrate

11‧‧‧Exhaust fan

17‧‧‧Exhaust pipe

Claims (13)

A film forming device with atomization for atomizing or dropletizing a raw material solution. The dropletization part, with the carrier gas will be in the atomization. a mist or droplet generated by the dropletizing portion is transported to a transport portion of the substrate, and a film forming portion that forms a film on the substrate by heat-treating the mist or the droplet, wherein the film forming portion is provided with the mist or The droplets are rotated back to produce a unit that is swirled back. The film forming apparatus of claim 1, wherein the swirling flow is inward flowing. The film forming apparatus according to claim 1, wherein the film forming portion is cylindrical or substantially cylindrical, and the mist or the inlet of the liquid droplet is provided on a side surface of the film forming portion. . The film forming apparatus according to claim 3, wherein the mist or the discharge port of the liquid droplet is provided at a position farther from the substrate than the feed port of the film forming portion. The film forming apparatus according to any one of claims 1 to 4, further comprising an exhaust fan. The film forming apparatus according to any one of claims 1 to 4, wherein the film forming portion has a hot plate. The film forming apparatus according to any one of claims 1 to 4, wherein, in the atomization. The droplet formation unit is provided with an ultrasonic vibrator. A film forming method comprising: transporting a mist or droplet obtained by atomizing or dropletizing a raw material solution with a carrier gas to a substrate disposed in a film forming chamber, and then thermally reacting the mist or droplet on the substrate; Forming a film in which the mist or the droplets are swirled back in the film forming chamber to produce a swirling flow. The film forming method as described in claim 8, wherein the swirling flow is inward flowing. The film forming method according to claim 8, wherein the film forming portion is cylindrical or substantially cylindrical, and the mist or the inlet of the liquid droplet is provided on a side surface of the film forming portion. . The film forming method according to claim 10, wherein the mist or the discharge port of the liquid droplet is provided at a distance from the substrate at a distance from the inlet of the film forming chamber. The film forming method according to claim 11, wherein an exhaust fan is further provided to perform the exhaust. The film forming method according to any one of claims 8 to 12, wherein the atomizing or dropletizing is performed by ultrasonic vibration.