Thin film deposition apparatus and method for depositing gallium nitride films

Abstract

Provided is a gallium nitride film formation method comprising disposing a substrate in a vacuum chamber so as to be opposite from a target including nitrogen and gallium, heating the substrate, supplying a sputtering gas to the vacuum chamber, supplying nitrogen radicals and hydrogen radicals to the vacuum chamber, and applying a voltage to the target to generate a plasma of the sputtering gas. Deposited on the substrate are gallium nitride which is produced by a recombination reaction between the nitrogen radicals and gallium released from the gallium of the target, and gallium nitride which is produced by a recombination reaction between gallium positive ions produced from the gallium of the target and nitrogen negative ions produced from the nitrogen radicals.

Description

Technical Field

[0001] One embodiment of the present invention relates to a film-forming apparatus for forming a gallium nitride film. Another embodiment of the present invention relates to a method for forming a gallium nitride film.

Background Art

[0002] In small and medium-sized display devices such as smartphones, display devices using liquid crystals or OLEDs (Organic Light Emitting Diodes) have already been commercialized. Among them, an OLED display device using an OLED, which is a self-emitting element, has advantages such as high contrast and no need for a backlight compared to a liquid crystal display device. However, since an OLED is composed of an organic compound, it is difficult to ensure the high reliability of an OLED display device due to the deterioration of the organic compound.

[0003] In recent years, as a next-generation display device, the development of a so-called micro-LED display device or mini-LED display device in which a tiny LED chip is mounted in a pixel of a circuit board has been underway. An LED is a self-emitting element similar to an OLED, but unlike an OLED, it is composed of a stable inorganic compound containing gallium (Ga) or indium (In), etc. Therefore, compared with an OLED display device, a micro-LED display device is likely to ensure high reliability. Furthermore, an LED chip has high luminous efficiency and can achieve high brightness. Therefore, a micro-LED display device or a mini-LED display device is expected as a next-generation display device with high reliability, high brightness, and high contrast.

[0004] Incidentally, gallium nitride films used in micro-LEDs and the like are generally deposited on sapphire substrates at high temperatures of 800°C to 1000°C using MOCVD (Metal Organic Chemical Vapor Deposition) or HVPE (Hydride Vapor Phase Epitaxy). However, in recent years, a method for depositing gallium nitride films by sputtering, which allows for deposition at relatively low temperatures, has been developed (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-164927 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] If gallium nitride films could be deposited at low temperatures, it would be possible to form micro-LEDs directly on glass substrates. However, gallium nitride films produced by sputtering have not been of sufficient quality.

[0007] One embodiment of the present invention aims to provide a film deposition apparatus capable of depositing a gallium nitride film at a low temperature, in view of the above-mentioned problems. Another embodiment of the present invention aims to provide a method for depositing a high-quality gallium nitride film. [Means for solving the problem]

[0008] A film deposition apparatus according to one embodiment of the present invention includes a vacuum chamber capable of creating a vacuum inside; a substrate support section provided inside the vacuum chamber and supporting a substrate; a target support section provided inside the vacuum chamber and supporting a target containing nitrogen and gallium; a sputtering gas supply section connected to the vacuum chamber and supplying sputtering gas to the vacuum chamber; a sputtering power supply that applies a voltage to the target and generates plasma from the sputtering gas supplied to the vacuum chamber; a first radical supply source connected to the vacuum chamber and capable of supplying nitrogen radicals and hydrogen radicals to the vacuum chamber; a second radical supply source connected to the vacuum chamber and capable of supplying chlorine radicals to the vacuum chamber; and a control section that controls at least one of the sputtering gas supply section, the sputtering power supply, the first radical supply source, and the second radical supply source.

[0009] A method for depositing a gallium nitride film according to one embodiment of the present invention includes arranging a substrate so as to face a target containing nitrogen and gallium in a vacuum chamber, heating the substrate, supplying sputtering gas to the vacuum chamber, supplying nitrogen radicals and hydrogen radicals to the vacuum chamber, and applying a voltage to the target to generate a sputtering gas plasma, thereby depositing gallium nitride on the substrate by a recombination reaction between gallium emitted from the target and nitrogen radicals, and gallium nitride produced by a recombination reaction between gallium cations generated from the gallium in the target and nitrogen anions generated from nitrogen radicals. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of a film deposition apparatus according to one embodiment of the present invention. [Figure 2] This is a block diagram showing the connection relationships of the control unit of a film deposition apparatus according to one embodiment of the present invention. [Figure 3] This is a flowchart illustrating a method for depositing a gallium nitride film according to one embodiment of the present invention. [Figure 4]This is a sequence diagram showing the timing of control by the control unit in a method for depositing a gallium nitride film according to one embodiment of the present invention. [Figure 5] This is a sequence diagram showing the timing of control by the control unit in a method for depositing a gallium nitride film according to one embodiment of the present invention. [Figure 6] This is a sequence diagram showing the timing of control by the control unit in a method for depositing a gallium nitride film according to one embodiment of the present invention. [Figure 7] This is a sequence diagram showing the timing of control by the control unit in a method for depositing a gallium nitride film according to one embodiment of the present invention. [Figure 8] This is a schematic diagram showing the substrate support section of a film deposition apparatus according to one embodiment of the present invention. [Figure 9] This is a schematic diagram illustrating the measurement of gallium nitride film thickness in a film deposition apparatus according to one embodiment of the present invention. [Figure 10] This is a schematic diagram showing the configuration of a light-emitting element related to one embodiment of the present invention. [Figure 11] This is a schematic diagram showing the configuration of a semiconductor device related to Attached Device. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the drawings. Note that each embodiment is merely an example, and any embodiment that a person skilled in the art could easily conceive by modifying it appropriately while maintaining the spirit of the invention is naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, or shape of each part compared to the actual embodiment. However, the illustrated shapes are merely examples and do not limit the interpretation of the present invention.

[0012] In this specification, expressions such as "α includes A, B, or C", "α includes any one of A, B, and C", "α includes one selected from the group consisting of A, B, and C", etc., unless otherwise specified, do not exclude the case where α includes a plurality of combinations of A to C. Furthermore, these expressions do not exclude the case where α includes other elements.

[0013] In this specification, for convenience of explanation, terms such as "upper" or "above" or "lower" or "below" are used. In principle, based on the substrate on which the structure is formed, the direction from the substrate towards the structure is defined as "upper" or "above". Conversely, the direction from the structure towards the substrate is defined as "lower" or "below". Therefore, in the expression of a structure on a substrate, the surface of the structure facing the substrate is the lower surface of the structure, and the opposite surface is the upper surface of the structure. Also, in the expression of a structure on a substrate, it only describes the vertical relationship between the substrate and the structure, and other members may be arranged between the substrate and the structure. Furthermore, the terms "upper" or "above" or "lower" or "below" mean the stacking order in a structure where multiple layers are stacked, and they do not necessarily have an overlapping positional relationship in a plan view.

[0014] In this specification, the characters such as "first", "second", or "third" appended to each component are for convenience of distinguishing each component and have no further meaning unless otherwise specified.

[0015] In this specification and the drawings, when collectively representing a plurality of identical or similar components, the same reference numerals are used. When separately representing each of these plurality of components, it may be represented by adding lowercase or uppercase alphabets. Also, when separately representing a plurality of parts within one component, hyphens and natural numbers may be used.

[0016] In this specification, cations and anions may be referred to as positive ions and negative ions respectively.

[0017] The following embodiments can be combined with each other as long as no technical contradiction occurs.

[0018] <First Embodiment> Referring to FIGS. 1 and 2, a film forming apparatus for a gallium nitride film according to an embodiment of the present invention will be described.

[0019] FIG. 1 is a schematic diagram showing the configuration of a film forming apparatus 10 according to an embodiment of the present invention.

[0020] As shown in FIG. 1, the film forming apparatus 10 includes a vacuum chamber 100, a substrate support portion 110, a heating portion 120, a target 130, a target support portion 140, a pump 150, a sputtering power source 160, a sputtering gas supply portion 170, a first radical supply source 180, a second radical supply source 190, and a control portion 200.

[0021] In the vacuum chamber 100, a substrate support portion 110, a heating portion 120, a target 130, and a target support portion 140 are provided. The substrate support portion 110 and the heating portion 120 are provided below in the vacuum chamber 100. The substrate is placed on the substrate support portion 110. The heating portion 120 is provided inside the substrate support portion 110 and can heat the substrate placed on the substrate support portion 110. The target 130 and the target support portion 140 are provided above in the vacuum chamber 100. The target 130 is supported by the target support portion 140 and is provided so as to face the substrate placed on the substrate support portion 110.

[0022] In FIG. 1, a configuration is shown in which the substrate support portion 110 and the heating portion 120 are provided below in the vacuum chamber 100 and the target 130 and the target support portion 140 are provided above in the vacuum chamber 100, but the positions where these are provided may be reversed.

[0023] The target 130 is gallium nitride containing nitrogen and gallium. Preferably, the composition ratio of gallium nitride in the target 130 is 0.7 to 2 for gallium relative to nitrogen. Since the nitrogen for the gallium nitride film deposited on the substrate is supplied from the target 130 and the first radical supply source 180, while the gallium for the gallium nitride film is supplied only from the target 130, it is even more preferable that the composition of gallium nitride in the target 130 has more gallium than nitrogen. Furthermore, it is preferable that the target support portion 140 is made of an yttria-based material that has corrosion resistance to chlorine, which is an etching gas (second gas) described later.

[0024] Outside the vacuum chamber 100, a pump 150, a sputtering power supply 160, a sputtering gas supply unit 170, a first radical supply source 180, and a second radical supply source 190 are provided.

[0025] Pump 150 is connected to the vacuum chamber 100 via piping 151. Pump 150 can evacuate the gas inside the vacuum chamber 100 through piping 151. In other words, the vacuum chamber 100 can be evacuated by pump 150 connected to the vacuum chamber 100. Furthermore, the pressure inside the vacuum chamber 100 can be kept constant by opening and closing valve 152 connected to piping 151. As pump 150, for example, a turbomolecular pump or a cryopump can be used.

[0026] The sputtering power supply 160 is electrically connected to the target 130 via wiring 161. The sputtering power supply 160 can generate a direct current (DC) voltage or an alternating current (AC) voltage and apply the generated voltage to the target 130. The AC voltage is 13.56 MHz. The sputtering power supply 160 can also apply a bias voltage to the target 130 and further apply a DC or AC voltage.

[0027] The sputtering power supply 160 may periodically change the voltage applied to the target 130. For example, a voltage can be applied to the target 130 for a period of 50 μsec to 10 msec, and then the application of the voltage to the target 130 can be stopped for a period of 2 μsec to 10 msec. In the film deposition apparatus according to this embodiment, a gallium nitride film is deposited by repeatedly alternating between periods when a voltage is applied to the target 130 and periods when the application of the voltage to the target 130 is stopped. In the following, the state in which a voltage is applied to the target 130 may be referred to as the ON state of the sputtering power supply 160, and the state in which no voltage is applied to the target 130 may be referred to as the OFF state of the sputtering power supply 160.

[0028] The sputtering gas supply unit 170 is connected to the vacuum chamber 100 via piping 171. The sputtering gas supply unit 170 can supply sputtering gas into the vacuum chamber 100 via piping 171. The flow rate of the sputtering gas can also be controlled by a mass flow controller 172 connected to piping 171. Argon (Ar) or krypton (Kr) can be used as the sputtering gas supplied from the sputtering gas supply unit 170.

[0029] The first radical supply source 180 is connected to a pipe 181 provided in the vacuum chamber 100 and can supply nitrogen radicals and hydrogen radicals into the vacuum chamber 100. The pipe 181 may also have one end facing the substrate support section 110. In this case, nitrogen radicals and hydrogen radicals can be irradiated from one end of the pipe 181 toward the substrate placed on the substrate support section 110. As will be described in detail later, the first radical supply source 180 can generate nitrogen radicals by plasma-forming a first gas containing nitrogen.

[0030] The second radical source 190 is connected to a pipe 191 provided inside the vacuum chamber 100 and can supply chlorine radicals into the vacuum chamber 100. The pipe 191 may also have one end facing the substrate support 110. In this case, chlorine radicals can be irradiated from one end of the pipe 191 toward the substrate placed on the substrate support 110. As will be described in detail later, the second radical source 190 can generate chlorine radicals by plasma-forming a second gas containing chlorine.

[0031] The first radical source 180 may be provided within the vacuum chamber 100 and generate nitrogen radicals within the vacuum chamber 100. Similarly, the second radical source 190 may be provided within the vacuum chamber 100 and generate chlorine radicals within the vacuum chamber 100.

[0032] The control unit 200 can control the operation of the film deposition apparatus 10 during the deposition of a gallium nitride film. The control unit 200 is a computer capable of performing arithmetic processing using data or information, and includes, for example, a central processing unit (CPU), a microprocessor (MPU), or random access memory (RAM). Specifically, the control unit 200 controls the operation of the film deposition apparatus 10 by executing a predetermined program. Here, with reference to Figure 2, the details of the control of the control unit 200 will be described.

[0033] Figure 2 is a block diagram showing the connection relationships of the control unit 200 of the film deposition apparatus 10 according to one embodiment of the present invention.

[0034] As shown in Figure 2, the control unit 200 is connected to the sputtering power supply 160 and the sputtering gas supply unit 170. Therefore, the control unit 200 can control the ON or OFF state of the sputtering power supply 160 and the start or stop of the supply of sputtering gas to the vacuum chamber 100. In Figure 2, the control unit 200 is shown as being connected to the sputtering gas supply unit 170, but the control unit 200 may also be connected to a mass flow controller 172, and the start or stop of the sputtering gas supply may be controlled by the mass flow controller 172.

[0035] Furthermore, the control unit 200 is connected to the first plasma power supply 182 and the first gas supply unit 183, which are installed in the first radical supply source 180. Therefore, the control unit 200 can control the ON or OFF state of the first plasma power supply 182 and the start or stop of the supply of the first gas. The first plasma power supply 182 plasmaizes the first gas supplied from the first gas supply unit 183. Therefore, when the control unit 200 starts supplying the first gas and controls the first plasma power supply 182 to turn ON, radicals of the first gas are supplied from the first radical supply source 180 to the vacuum chamber 100. The first gas is a gas containing nitrogen and hydrogen, such as a nitrogen-hydrogen mixed gas (N2 / H2 mixed gas) or ammonia gas (NH3 gas). Therefore, nitrogen radicals and hydrogen radicals are supplied as radicals of the first gas from the first radical supply source 180 to the vacuum chamber 100. Furthermore, when the control unit 200 starts supplying the first gas and controls the first plasma power supply 182 to be turned off, the first gas may be supplied to the vacuum chamber 100 from the first radical supply source 180.

[0036] Furthermore, the control unit 200 is connected to the second plasma power supply 192 and the second gas supply unit 193, which are installed in the second radical supply source 190. Therefore, the control unit 200 can control the ON or OFF state of the second plasma power supply 192 and the start or stop of the supply of the second gas. The second plasma power supply 192 plasmaizes the second gas supplied from the second gas supply unit 193. Therefore, when the control unit 200 starts supplying the second gas and controls the second plasma power supply 192 to turn ON, radicals of the second gas are supplied from the second radical supply source 190 to the vacuum chamber 100. The second gas is a chlorine-containing gas, such as chlorine gas (Cl2 gas) or boron trichloride gas (BCl3 gas). Therefore, chlorine radicals are supplied as the second radicals from the second radical supply source 190 to the vacuum chamber 100. Furthermore, when the control unit 200 starts supplying the second gas and controls the second plasma power supply 192 to be turned off, the second gas may be supplied to the vacuum chamber 100 from the second radical supply source 190.

[0037] The control unit 200 may control the pump 150 so that the inside of the vacuum chamber 100 is maintained at a predetermined pressure. Furthermore, the control unit 200 may control the heating unit 120 so that the substrate placed on the substrate support unit 110 is heated to a predetermined temperature.

[0038] As will be described in detail later, in the film deposition apparatus 10 according to one embodiment of the present invention, by repeatedly performing gallium nitride film formation, etching, and impurity reduction treatments using nitrogen radicals, hydrogen radicals, and chlorine radicals, a high-quality gallium nitride film can be deposited on a substrate even at low temperatures such as 400°C to 600°C.

[0039] Furthermore, the film deposition apparatus 10 can also deposit nitride films other than gallium nitride films by using a material other than gallium nitride for the target 130.

[0040] <Second Embodiment> Referring to Figures 3 and 4, a method for forming a gallium nitride film, which is one embodiment of the present invention, will be described. Since the gallium nitride film described in this embodiment is formed using a film deposition apparatus 10, for convenience, the following description may refer to the reference numerals shown in Figures 1 and 2.

[0041] Figure 3 is a flowchart illustrating a method for depositing a gallium nitride film according to one embodiment of the present invention. In the gallium nitride film deposit method shown in Figure 3, steps S100 to S210 are executed sequentially.

[0042] In step S100, the substrate is placed on the substrate support portion 110 so as to face the target 130. In the film deposition apparatus 10, for example, a glass substrate or a quartz substrate can be used as the substrate. Alternatively, a glass substrate or a quartz substrate on which an aluminum nitride film has been formed can also be used as the substrate.

[0043] In step S110, the substrate is heated to a predetermined temperature by the heating unit 120. The predetermined temperature is, for example, 400°C or more and 600°C or less.

[0044] In step S120, the pump 150 evacuates the gas from the vacuum chamber 100 so that the vacuum level is below a predetermined level. The predetermined vacuum level is, for example, 10 -6 Pa is the most common answer, but it is not limited to this.

[0045] In step S130, the first radical source 180 is controlled, and nitrogen radicals and hydrogen radicals are supplied from the first radical source 180 to the vacuum chamber 100.

[0046] In step S140, the sputtering gas supply unit 170 is controlled, and sputtering gas is supplied from the sputtering gas supply unit 170 to the vacuum chamber 100. The flow rate of the sputtering gas is also adjusted by the mass flow controller 172 so that the pressure inside the vacuum chamber 100 is a predetermined pressure. The predetermined pressure is, for example, between 0.1 Pa and 10 Pa.

[0047] In step S150, the sputtering power supply 160 is controlled, and a predetermined voltage is applied to the target 130 so that the target 130 acts as the cathode relative to the substrate (the sputtering power supply 160 is turned on). This causes the sputtering gas supplied to the vacuum chamber 100 to be plasma-generated, generating cations and electrons in the sputtering gas. The ions in the sputtering gas are accelerated by the potential difference between the substrate and the target 130 and collide with the target 130. As a result, sputtered gallium and gallium cations are emitted from the target 130.

[0048] In step S150, nitrogen radicals are supplied to the vacuum chamber 100 from the first radical source 180. As a result, gallium released from the target 130 recombines with the nitrogen radicals to produce gallium nitride. The generated gallium nitride is deposited on the substrate to form a gallium nitride film.

[0049] In step S150, gallium nitride is also produced by another recombination reaction. Nitrogen has high electronegativity and readily attracts electrons. Therefore, nitrogen radicals react with electrons in the vacuum chamber 100 to produce nitrogen anions. The generated nitrogen anions recombine with gallium cations present near the substrate to produce gallium nitride. The generated gallium nitride is deposited on the substrate, forming a gallium nitride film. Since the recombination reaction between cations and anions releases a large amount of energy, a gallium nitride film can be formed on the substrate even at low substrate temperatures.

[0050] Incidentally, oxygen may remain in the vacuum chamber 100. In this case, gallium cations react with the residual oxygen in the vacuum chamber 100 to produce gallium oxide. Since the growth of the gallium nitride film is inhibited when gallium oxide is produced, it is preferable that the residual oxygen in the vacuum chamber 100 be reduced as much as possible. In step S150, not only nitrogen radicals but also hydrogen radicals are supplied to the vacuum chamber 100. Hydrogen radicals react with the residual oxygen to produce water (water vapor). The produced water vapor is then exhausted from the vacuum chamber 100 by the pump 150. In other words, in the film deposition apparatus 10, the residual oxygen in the vacuum chamber 100 is reduced, so the production of gallium oxide is suppressed, and as a result, the gallium nitride film formed on the substrate is a high-quality film.

[0051] As mentioned above, hydrogen radicals have the effect of removing residual oxygen that inhibits the formation of gallium nitride. Furthermore, hydrogen radicals can react with gallium cations to produce gallium hydride cations. Gallium hydride cations are highly reactive and readily react with nitrogen anions to produce gallium nitride. Therefore, hydrogen radicals also have the effect of promoting the formation of gallium nitride.

[0052] In step S160, the sputtering power supply 160 is controlled, and the application of voltage to the target 130 is stopped (the sputtering power supply 160 is turned off). As a result, the plasma disappears, but the deposition apparatus 10 can still generate gallium nitride in this state. Specifically, in step S160, gallium nitride can be generated by utilizing the metastable state of the sputtering gas (noble gas). The details of gallium nitride generation in step S160 will now be explained.

[0053] It is known that long-lived metastable noble gas atoms exist in noble gas plasmas. For example, the metastable state energies of argon and krypton atoms are 11.61 eV and 9.91 eV, respectively. Such metastable argon or krypton atoms are generated in the sputtering plasma and, due to their long lifetime, can persist even after the plasma has disappeared. In other words, metastable argon or krypton atoms can persist even after the application of voltage to the target 130 is stopped.

[0054] After the voltage application to target 130 is stopped, nitrogen molecules, as well as nitrogen radicals, are present in the vacuum chamber 100. The dissociation energy from nitrogen molecules to nitrogen atoms due to electron collisions is 9.756 eV, which is close to the metastable state energy of argon or krypton atoms. Therefore, when nitrogen molecules collide with metastable argon or krypton atoms, a dissociation reaction of the nitrogen molecules occurs, generating nitrogen radicals. In other words, even after the voltage application to target 130 is stopped, nitrogen radicals are generated by metastable argon or krypton atoms. As mentioned above, nitrogen has high electronegativity, so nitrogen radicals react with electrons in the vacuum chamber 100 to produce nitrogen anions. In step S160, nitrogen radicals are supplied to the vacuum chamber 100 from the first radical supply source 180. The supplied nitrogen radicals react with electrons in the vacuum chamber 100 to produce nitrogen anions. The nitrogen anions generated in this way recombine with gallium cations present near the substrate to produce gallium nitride. The generated gallium nitride is deposited on the substrate, forming a gallium nitride film.

[0055] Therefore, in step S160, gallium nitride can be efficiently produced by utilizing not only nitrogen radicals supplied from the first radical source 180, but also metastable argon atoms or krypton atoms.

[0056] In step S170, the first radical source 180 is controlled, and the supply of nitrogen radicals and hydrogen radicals to the vacuum chamber 100 is stopped.

[0057] In step S180, the second radical source 190 is controlled, and chlorine radicals are supplied from the second radical source 190 to the vacuum chamber 100. The gallium nitride film formed in steps S150 and S160 includes not only crystalline regions but also amorphous regions. Therefore, in step S180, chlorine radicals are used to etch the amorphous regions of the gallium nitride film. This etching improves the crystallinity of the gallium nitride film formed on the substrate. The bonding between gallium and nitrogen is weaker in the amorphous regions than in the crystalline regions. Therefore, selective etching of the amorphous regions is possible. In addition, the boiling point of gallium chloride produced by etching is approximately 200°C at room temperature. Therefore, near the substrate heated to above 400°C, gallium chloride is a gas, and gallium nitride is not deposited on the substrate.

[0058] In step S190, the sputtering power supply 160 is controlled, and a predetermined voltage is applied to the target 130 so that the target 130 becomes the cathode relative to the substrate (the sputtering power supply 160 is turned on). This causes the chlorine radicals supplied to the vacuum chamber 100 to be converted into plasma. Chlorine has high electronegativity and readily attracts electrons. Therefore, the chlorine radicals react with electrons in the plasma to generate chlorine anions. Thus, in step S190, etching of the amorphous region of the gallium nitride film can be performed not only using chlorine radicals but also using chlorine anions. As a result, the amorphous region of the gallium nitride film can be etched efficiently.

[0059] In step S200, the sputtering power supply 160 is controlled to stop the application of voltage to the target 130 (the sputtering power supply 160 is turned off).

[0060] In step S210, the second radical source 190 is controlled, and the supply of chlorine radicals to the vacuum chamber 100 is stopped.

[0061] In the gallium nitride film deposition method according to this embodiment, a high-quality gallium nitride film with improved crystallinity can be deposited on a substrate by repeating steps S130 to S210. Here, with reference to Figure 4, the details of the timing of control by the control unit 200 will be explained.

[0062] Figure 4 is a sequence diagram showing the timing of control by the control unit 200 in a method for depositing a gallium nitride film according to one embodiment of the present invention. Note that the sequence diagram shown in Figure 4 is an example, and the control by the control unit 200 is not limited to this. Several modifications will be described later.

[0063] Figure 4 shows the first to fifth periods T1 to T5 related to the potassium nitride film deposition process. The sputtering power supply 160 is ON during the first period T1 and the fourth period T4, and OFF during the second period T2, the third period T3, and the fifth period T5. The ON period of the sputtering power supply 160 is, for example, 50 μsec to 10 msec. To stabilize the plasma, it is preferable that the ON period of the sputtering power supply 160 is 50 μsec or longer. The OFF period of the sputtering power supply 160 is, for example, 2 μsec to 10 msec. It is preferable that the OFF period of the sputtering power supply 160 is longer than the lifetime of the sputtering gas in the metastable state.

[0064] (First period T1) The first period T1 is the ON period of the sputtering power supply 160. During the first period T1, sputtering gas is supplied to the vacuum chamber 100 from the sputtering gas supply unit 170. Also, the first gas is supplied from the first gas supply unit 183, and the first plasma power supply 182 is ON. That is, nitrogen radicals and hydrogen radicals are generated in the first radical supply source 180, and the generated nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber 100. On the other hand, the supply of the second gas from the second gas supply unit 193 is stopped, and the second plasma power supply 192 is OFF. That is, chlorine radicals are not generated in the second radical supply source 190, and chlorine radicals are not supplied to the vacuum chamber 100.

[0065] During the first period T1, step S150 described above is performed. That is, during the first period, the sputtering gas supplied to the vacuum chamber 100 is plasma-generated, generating cations and electrons from the sputtering gas. The cations from the sputtering gas collide with the target 130, and sputtered gallium and gallium cations are emitted from the target 130. The gallium emitted from the target 130 recombines with nitrogen radicals to produce gallium nitride. Also, the nitrogen radicals supplied to the vacuum chamber 100 react with electrons to generate nitrogen anions. The generated nitrogen anions recombine with gallium cations present near the substrate to produce gallium nitride. The generated gallium nitride is deposited on the substrate, forming a gallium nitride film.

[0066] (Second period T2) The second period T2 is included in the off period of the sputtering power supply 160. During the second period T2, the supply of sputtering gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped. At the same time, the first plasma power supply 182 is turned off while the first gas is supplied from the first gas supply unit 183. Therefore, the first gas containing nitrogen, as well as nitrogen radicals and hydrogen radicals, is supplied to the vacuum chamber 100 from the first radical supply source 180. The supply of the second gas from the second gas supply unit 193 is stopped, and the second plasma power supply 192 is turned off. In other words, no chlorine radicals are generated in the second radical supply source 190, and therefore no chlorine radicals are supplied to the vacuum chamber 100 from the second radical supply source 190.

[0067] In the second period T2, step S160 described above is performed. That is, in the second period T2, gallium nitride is produced by the recombination reaction of nitrogen anions and gallium cations using a metastable sputtering gas. The produced gallium nitride is deposited on the substrate to form a gallium nitride film.

[0068] In this embodiment, the deposition rate of the gallium nitride film can be improved by depositing the gallium nitride film not only during the first period T1 but also during the second period T2.

[0069] (Third period T3) The third period T3 is included in the off period of the sputtering power supply 160. During the third period T3, the second gas is supplied from the second gas supply unit 193, and the second plasma power supply 192 is in the ON state. That is, chlorine radicals are generated in the second radical supply source 190, and the generated chlorine radicals are supplied to the vacuum chamber 100. Also, while the sputtering power supply 160 remains in the OFF state, the supply of sputtering gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is started or stopped. The supply of the first gas from the first gas supply unit 183 is stopped, and the first plasma power supply 182 is in the OFF state. That is, nitrogen radicals and hydrogen radicals are not generated in the first radical supply source 180, and therefore nitrogen radicals and hydrogen radicals are not supplied from the first radical supply source 180 to the vacuum chamber 100.

[0070] In the third period T3, step S180 described above is performed. That is, in the third period T3, etching of the amorphous region of the gallium nitride film is performed using chlorine radicals.

[0071] (Fourth period T4) The fourth period T4 is the ON period of the sputtering power supply 160. During the fourth period T4, sputtering gas is supplied to the vacuum chamber 100 from the sputtering gas supply unit 170. Also, the second gas is supplied from the second gas supply unit 193, and the second plasma power supply 192 is ON. That is, chlorine radicals are generated in the second radical supply source 190, and the generated chlorine radicals are supplied to the vacuum chamber 100. The supply of the first gas from the first gas supply unit 183 is stopped, and the first plasma power supply 182 is OFF. That is, nitrogen radicals and hydrogen radicals are not generated in the first radical supply source 180, and therefore nitrogen radicals and hydrogen radicals are not supplied from the first radical supply source 180 to the vacuum chamber 100.

[0072] In the fourth period T4, step S190 described above is performed. That is, in the fourth period T4, etching of the amorphous region of the gallium nitride film is performed using chlorine radicals and chlorine anions.

[0073] In this embodiment, the crystallinity of the gallium nitride film can be improved by etching the amorphous region of the gallium nitride film not only during the third period T3 but also during the fourth period T4.

[0074] The length of the fourth period T4 may be the same as or different from the length of the first period T1.

[0075] (Fifth period T5) The fifth period is included in the off period of the sputtering power supply 160. During the fifth period T5, the supply of sputtering gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. At the same time, the first gas is supplied from the first gas supply unit 183, and the first plasma power supply 182 is turned on. As a result, nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber 100 from the first radical supply source 180. The supply of the second gas from the second gas supply unit 193 is stopped, and the second plasma power supply 192 is turned off. In other words, no chlorine radicals are generated in the second radical supply source 190, and therefore no chlorine radicals are supplied to the vacuum chamber 100 from the second radical supply source 190.

[0076] During the fifth period T5, hydrogen radicals supplied to the vacuum chamber 100 react with chlorine in the vacuum chamber 100 or in the gallium nitride film to produce hydrogen chloride. The generated hydrogen chloride is then evacuated from the vacuum chamber 100 by a pump, reducing the residual chlorine in the vacuum chamber 100 or in the gallium nitride film. In other words, the hydrogen radicals during the fifth period T5 remove chlorine, which is an impurity in the gallium nitride film, thus reducing the impurities in the gallium nitride film. Consequently, the gallium nitride film becomes a high-quality film with a low impurity concentration.

[0077] According to a method for forming a gallium nitride film according to one embodiment of the present invention, the potassium nitride film formation process, the amorphous region etching process, and the impurity reduction process are repeated as the first period T1 to the fifth period T5 are repeated. As a result, the gallium nitride film formed on the substrate has high crystallinity and is a high-quality film.

[0078] <Example 1> Referring to Figure 5, a modified example of the method for forming a gallium nitride film according to one embodiment of the present invention will be described. Note that in the following, configurations similar to those described in the second embodiment may be omitted from the description.

[0079] Figure 5 is a sequence diagram showing the timing of control by the control unit 200 in a method for depositing a gallium nitride film according to one embodiment of the present invention. As shown in Figure 5, the method for depositing a gallium nitride film according to this modified example includes a fourth period T4'.

[0080] The fourth period T4' is the ON period of the sputtering power supply 160. During the fourth period T4', sputtering gas is not supplied from the sputtering gas supply unit 170 to the vacuum chamber 100. If a stable plasma is formed by the supplied chlorine radicals, it is not necessary to supply sputtering gas to the vacuum chamber 100. Because a stable plasma is formed, chlorine radicals and chlorine anions are generated, allowing etching of the amorphous region of the gallium nitride film.

[0081] <Modification 2> Referring to Figure 6, another modified example of the method for forming a gallium nitride film according to one embodiment of the present invention will be described. Note that in the following, configurations similar to those described in the second embodiment may be omitted from the description.

[0082] Figure 6 is a sequence diagram showing the timing of control by the control unit 200 in a method for depositing a gallium nitride film according to one embodiment of the present invention. As shown in Figure 6, the method for depositing a gallium nitride film according to this modified example includes a fourth period T4''.

[0083] The fourth period T4'' is the ON period of the sputtering power supply 160. During the fourth period T4'', the second gas is supplied from the second gas supply unit 193, but the second plasma power supply 192 is OFF. Therefore, no chlorine radicals are generated in the second radical supply source 190, and the second gas is supplied to the vacuum chamber 100. During the fourth period T4'', since the sputtering power supply 160 is ON, the second gas supplied to the vacuum chamber 100 is plasma-generated, and chlorine radicals and chlorine anions are generated. Therefore, the chlorine radicals and chlorine anions generated in the vacuum chamber 100 can be used to etch the amorphous region of the gallium nitride film.

[0084] <Variation 3> Referring to Figure 7, yet another modification of the method for forming a gallium nitride film according to one embodiment of the present invention will be described. Note that in the following, configurations similar to those described in the second embodiment may be omitted from the description.

[0085] Figure 7 is a sequence diagram showing the timing of control by the control unit 200 in a method for depositing a gallium nitride film according to one embodiment of the present invention. In the method for depositing a gallium nitride film according to this modified example, a nitrogen-hydrogen mixed gas (N2 / H2 mixed gas) is used as the first gas, but the nitrogen gas and hydrogen gas are supplied from the 1-1 gas supply unit and the 1-2 gas supply unit, respectively. That is, the nitrogen gas and hydrogen gas are supplied from separate gas supply sources. Therefore, the control unit 200 can independently control the start or stop of the supply of nitrogen gas, or the start or stop of the supply of hydrogen gas. As shown in Figure 7, the method for depositing a gallium nitride film according to this modified example includes a second period T2' and a fifth period T5'.

[0086] The second period T2' is included in the off period of the sputtering power supply 160. During the second period T2', the supply of sputtering gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped. Also, nitrogen gas and hydrogen gas are supplied from the 1-1 gas supply unit and the 1-2 gas supply unit, respectively, while the first plasma power supply 182 is turned off. Therefore, not only nitrogen radicals and hydrogen radicals, but also nitrogen gas and hydrogen gas are supplied to the vacuum chamber 100. The supply of the second gas from the second gas supply unit 193 is stopped, and the second plasma power supply 192 is turned off. In other words, no chlorine radicals are generated in the second radical supply source 190, and chlorine radicals are not supplied from the second radical supply source 190 to the vacuum chamber 100.

[0087] Furthermore, during the second period T2', after the supply of nitrogen gas from the 1-1 gas supply unit is stopped, the supply of hydrogen gas from the 1-2 gas supply unit is also stopped. This control promotes the surface migration of hydrogen to the gallium deposited on the substrate surface during the off-period of the sputtering power supply 160. In other words, by terminating the gallium on the substrate surface with hydrogen, the formation of gallium oxide on the substrate surface can be suppressed. In addition, the flatness of the formed gallium nitride film can be improved.

[0088] The fifth period T5' is included in the off period of the sputtering power supply 160. During the fifth period T5', the supply of sputtering gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. Also, nitrogen gas and hydrogen gas are supplied from the 1-1 gas supply unit and the 1-2 gas supply unit, respectively, and the first plasma power supply 182 is turned on. As a result, nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber 100. The supply of the second gas from the second gas supply unit 193 is stopped, and the second plasma power supply 192 is turned off. That is, no chlorine radicals are generated in the second radical supply source 190, and therefore no chlorine radicals are supplied from the second radical supply source 190 to the vacuum chamber 100.

[0089] Furthermore, during the fifth period T5', after the supply of hydrogen gas from the 1-2 gas supply unit is started, the supply of nitrogen gas from the 1-1 gas supply unit is started. This control allows for the efficient removal of residual chlorine on the substrate surface using hydrogen gas before supplying nitrogen gas during the off-period of the sputtering power supply 160.

[0090] The sequence diagram in Figure 7 shows an example in which the cessation of nitrogen gas supply and hydrogen gas supply, or the cessation of hydrogen gas supply and the start of nitrogen gas supply and the start of hydrogen gas supply are performed sequentially. However, the cessation of nitrogen gas supply and hydrogen gas supply, or the cessation of hydrogen gas supply and the start of nitrogen gas supply and the start of hydrogen gas supply may be performed simultaneously. Alternatively, a first plasma power supply 182 may be provided in each of the 1-1 gas supply unit and the 1-2 gas supply unit, and the start or cessation of nitrogen radical supply and the start or cessation of hydrogen radical supply may be controlled independently.

[0091] Furthermore, the method for forming a gallium nitride film according to this modified example can also be applied to other modified examples.

[0092] <Third Embodiment> Referring to Figures 8 and 9, the substrate support portion 110A of the gallium nitride film deposition apparatus 10 according to one embodiment of the present invention will be described. Note that in the following, configurations similar to those described in the first and second embodiments may be omitted from the description.

[0093] Figure 8 is a schematic diagram showing the substrate support portion 110A of a film deposition apparatus 10 according to one embodiment of the present invention.

[0094] As shown in Figure 8, the film deposition apparatus 10 is equipped with an irradiation unit 111A that irradiates light onto the substrate 510 placed on the substrate support unit 110A, and a light receiving unit 112A that receives light reflected from the substrate 510. The installation positions of the irradiation unit 111A and the light receiving unit 112A within the film deposition apparatus 10 are not particularly limited. The light emitted by the irradiation unit 111A is either infrared light or visible light.

[0095] Figure 9 is a schematic diagram illustrating the measurement of gallium nitride film thickness in a film deposition apparatus 10 according to one embodiment of the present invention.

[0096] As described in the second embodiment, in the deposition of a gallium nitride film using the deposition apparatus 10, there is an off period for the sputtering power supply 160. During this off period, no plasma is formed in the vacuum chamber 100. Therefore, when light L1 is irradiated from the irradiation unit 111A, the light receiving unit 112A can receive light reflected from the substrate 510 and the gallium nitride film 520 formed on the substrate.

[0097] The substrate 510, the gallium nitride film 520, and the atmosphere inside the vacuum chamber 100 each have different refractive indices. Therefore, the light L1 irradiated from the irradiation unit 111A not only passes through the substrate 510 and the gallium nitride film 520, but is also reflected at the interface between the substrate 510 or the buffer layer formed on the substrate 510 and the gallium nitride film 520, or at the surface of the gallium nitride film 520. In other words, the light receiving unit 112A receives the light L2 that has been multiple-reflected. As the flat gallium nitride film 520 grows, the intensity of the light L2 received by the light receiving unit 112A undergoes periodic oscillations due to the interference of reflected light from the substrate 510 and the gallium nitride film 520. That is, the light received by the light receiving unit 112A exhibits oscillations in reflectivity and is detected as a periodic pattern. Specifically, if the wavelength of light L1 is λ, the optical path difference 2nd of light L2 is expressed by the equation 2nd = kλ (where k is a natural number). Here, n is the refractive index of the gallium nitride film 520, and d is the thickness of the gallium nitride film 520. Therefore, based on the periodic pattern and the above formula, the thickness d of the gallium nitride film 520 can be calculated.

[0098] In a film deposition apparatus 10 according to one embodiment of the present invention, the film thickness of the gallium nitride film can be measured by irradiating light during the off period of the sputtering power supply 160 and utilizing interference phenomena. Therefore, the film deposition apparatus 10 can control the film thickness of the gallium nitride film being deposited.

[0099] <Fourth Embodiment> Figure 10 is a schematic diagram showing the configuration of a light-emitting element 1000 according to one embodiment of the present invention.

[0100] As shown in Figure 10, the light-emitting element 1000 includes a substrate 1010, a barrier layer 1020, a buffer layer 1030, an n-type semiconductor layer 1040, a light-emitting layer 1050, a p-type semiconductor layer 1060, an n-type electrode 1070, and a p-type electrode 1080. The light-emitting element 1000 is a so-called LED (Light Emitting Diode), but is not limited to this.

[0101] As the substrate 1010, for example, a glass substrate or a quartz substrate can be used. As the barrier layer 1020, for example, a silicon nitride film can be used. As the buffer layer 1030, for example, an aluminum nitride film can be used. As the n-type semiconductor layer 1040, a silicon-doped gallium nitride film can be used. As the light-emitting layer 1050, a laminate in which indium gallium nitride films and gallium nitride films are alternately stacked can be used. As the p-type semiconductor layer 1060, a magnesium-doped gallium nitride film can be used. As the n-type electrode 1070, a metal such as indium can be used. As the p-type electrode 1080, a metal such as palladium or gold can be used. In addition, in the light-emitting element 1000 according to this embodiment, a configuration without a barrier layer 1020 can also be applied.

[0102] The manufacturing method for the light-emitting element 1000 is as follows: A silicon nitride film and an aluminum nitride film are sequentially deposited on a substrate 1010 to form a barrier layer 1020 and a buffer layer 1030. A silicon-doped gallium nitride film is then deposited on the buffer layer 1030. An indium gallium nitride film and a gallium nitride film are alternately deposited on the buffer layer 1030 to form a laminate. A magnesium-doped gallium nitride film is then deposited on the laminate. Next, the magnesium-doped gallium film, the laminate, and the silicon-doped gallium nitride film are etched using photolithography to form a p-type semiconductor layer 1060, a light-emitting layer 1050, and an n-type semiconductor layer 1040. At this time, the etching is performed in such a way that a portion of the surface of the silicon-doped gallium nitride film is exposed. An n-type electrode 1070 and a p-type electrode 1080 are formed on the n-type semiconductor layer 1040 and the p-type semiconductor layer 1060, respectively.

[0103] In this embodiment, the deposition apparatus 10 can be used to deposit not only a gallium nitride film for the light-emitting layer 1050, but also an aluminum nitride film for the light-emitting layer 1050. When depositing an aluminum gallium nitride film, aluminum gallium nitride containing nitrogen, aluminum, and gallium can be used as the target 130 of the deposition apparatus 10. Alternatively, two vacuum chambers can be connected via a substrate transport unit, and a gallium nitride film can be deposited in one vacuum chamber, and then aluminum gallium nitride can be deposited in the other vacuum chamber without breaking the vacuum.

[0104] Furthermore, the film deposition apparatus 10 can also be used to deposit an aluminum nitride film for the buffer layer 1030, a silicon-doped gallium nitride film for the n-type semiconductor layer 1040, or a magnesium-doped gallium nitride film for the p-type semiconductor layer 1060.

[0105] As described above, the light-emitting element 1000 according to this embodiment can be fabricated using a gallium nitride film formed using a film deposition apparatus 10, and therefore can be manufactured using a substrate with low heat resistance, such as a glass substrate.

[0106] <Fifth Embodiment> Figure 11 is a schematic diagram showing the configuration of semiconductor device 2000 according to one embodiment of the present invention.

[0107] As shown in Figure 11, the semiconductor device 2000 includes a substrate 2010, a barrier layer 2020, a buffer layer 2030, a gallium nitride layer 2040, a first aluminum gallium nitride layer 2050, a second aluminum gallium nitride layer 2060, a third aluminum gallium nitride layer 2070, a source electrode 2080, a drain electrode 2090, a gate electrode 2100, a first insulating layer 2110, a second insulating layer 2120, and a shield electrode 2130. The semiconductor device 2000 is a so-called HEMT (High Electron Mobility Transistor), but is not limited to this.

[0108] As the substrate 2010, for example, a glass substrate or a quartz substrate can be used. As the barrier layer 2020, for example, a silicon nitride film can be used. As the buffer layer 2030, for example, an aluminum nitride film can be used. As the gallium nitride layer 2040, a gallium nitride film can be used. As the first aluminum gallium nitride layer 2050, an aluminum gallium nitride film can be used. As the second aluminum gallium nitride layer 2060, for example, a silicon-doped gallium nitride film can be used. As the third aluminum gallium nitride layer 2070, an aluminum gallium nitride film can be used. As the source electrode 2080 and drain electrode 2090, for example, a metal such as titanium or aluminum can be used. As the gate electrode 2100, for example, a metal such as nickel or gold can be used. As the first insulating layer 2110, for example, a silicon nitride film can be used. As the second insulating layer 2120, for example, a silicon oxide film can be used. For example, a multilayer metal such as aluminum / titanium (Al / Ti) can be used as the shield electrode 2130. Furthermore, in the semiconductor element 2000 according to this embodiment, a configuration without the barrier layer 1020 can also be applied.

[0109] The semiconductor device 2000 is manufactured as follows: A silicon nitride film, an aluminum nitride film, a gallium nitride film, and an aluminum gallium nitride film are deposited on a substrate 2010 to form a barrier layer 2020, a buffer layer 2030, a gallium nitride layer 2040, and a first aluminum gallium nitride layer 2050. A silicon-doped aluminum gallium nitride film and an aluminum gallium nitride film are deposited on the first aluminum gallium nitride layer 2050. Next, the aluminum gallium nitride film and the silicon-doped aluminum gallium nitride film are etched using photolithography to form a third aluminum gallium nitride layer 2070 and a second aluminum gallium nitride layer 2060. At this time, the silicon-doped aluminum gallium nitride film is etched in such a way that a portion of its surface is exposed. A source electrode 2080 and a drain electrode 2090 are formed on the second aluminum gallium nitride layer 2060. Furthermore, a gate electrode 2100 is formed on the third aluminum gallium nitride layer 2070. A silicon nitride film and a silicon oxide film are sequentially deposited to cover the source electrode 2080, the drain electrode 2090, and the gate electrode 2100, forming a first insulating layer 2110 and a second insulating layer 2120. A shield electrode 2130 is formed on the second insulating layer 2120.

[0110] In this embodiment, the film deposition apparatus 10 can be used to deposit not only the gallium nitride film of the gallium nitride layer 2040, but also the aluminum nitride film of the buffer layer 2030, the aluminum nitride film of the first aluminum gallium nitride layer 2050, the silicon-doped aluminum gallium nitride film of the second aluminum gallium nitride layer 2060, and the aluminum gallium nitride film of the third aluminum gallium nitride layer 2070.

[0111] As described above, the semiconductor element 2000 according to this embodiment can be fabricated using a gallium nitride film deposited using the film deposition apparatus 10, and therefore can be manufactured using a substrate with low heat resistance, such as a glass substrate.

[0112] The embodiments described above as examples of the present invention can be combined and implemented as appropriate, insofar as they do not contradict each other. Furthermore, any modifications made by those skilled in the art to each embodiment, such as adding, deleting, or changing components, or adding, omitting, or changing processes, are also included within the scope of the present invention, as long as they retain the essence of the present invention.

[0113] Any effects or benefits other than those brought about by the embodiments described above, if they are clear from the description herein or easily predictable to a person skilled in the art, are naturally considered to be brought about by the present invention. [Explanation of Symbols]

[0114] 10: Film deposition apparatus, 100: Vacuum chamber, 110: Substrate support section, 111A: Irradiation section, 112A: Light receiving section, 120: Heating section, 130: Target, 140: Target support section, 150: Pump, 151: Piping, 152: Valve, 160: Sputtering power supply, 161: Wiring, 170: Sputtering gas supply section, 171: Piping, 172: Mass flow controller, 180: First radical supply source, 181: Piping, 182: First plasma power supply, 183: First gas supply section, 190: Second radical supply source, 191: Piping, 192: Second plasma power supply, 193: Second gas supply section, 200: Control section, 510: Substrate, 520: Gallium nitride film, 1000: Light-emitting element, 1010: Substrate, 1020: Barrier layer, 1030: Buffer layer, 1040: n-type semiconductor layer, 1050: Light-emitting layer, 1060: p-type semiconductor layer, 1070: n-type electrode, 1080: p-type electrode, 2000: Semiconductor element, 2010: Substrate, 2020: Barrier layer, 2030: Buffer layer, 2040: Gallium nitride layer, 2050: First aluminum gallium nitride layer, 2060: Second aluminum gallium nitride layer, 2070: Third aluminum gallium nitride layer, 2080: Source electrode, 2090: Drain electrode, 2100: Gate electrode, 2110: First insulating layer, 2120: Second insulating layer, 2130: Shield electrode

Claims

1. A vacuum chamber capable of creating a vacuum inside, A substrate support portion is provided within the vacuum chamber to support the substrate, A target support section provided within the vacuum chamber, which supports a target containing nitrogen and gallium, A sputtering gas supply unit connected to the vacuum chamber and supplying sputtering gas to the vacuum chamber, A sputtering power supply that applies a voltage to the target and generates plasma from the sputtering gas supplied to the vacuum chamber, A first radical supply source connected to the vacuum chamber and capable of supplying nitrogen radicals and hydrogen radicals to the vacuum chamber, A second radical source connected to the vacuum chamber and capable of supplying chlorine radicals to the vacuum chamber, A film deposition apparatus comprising: a sputtering gas supply unit; a sputtering power supply; a first radical supply source; and a control unit for controlling at least one of the second radical supply sources.

2. The film deposition apparatus according to claim 1, wherein the control unit controls the second radical supply source so as not to supply the chlorine radical when the nitrogen radical and the hydrogen radical are supplied from the first radical supply source.

3. The film deposition apparatus according to claim 1, wherein the control unit controls the first radical supply source so as not to supply the nitrogen radical and the hydrogen radical when the chlorine radical is supplied from the second radical supply source.

4. The film deposition apparatus according to claim 1, wherein the control unit controls the first radical supply source to supply the nitrogen radicals and hydrogen radicals to the vacuum chamber for a certain period of time after turning off the sputtering power supply.

5. The film deposition apparatus according to claim 1, wherein the control unit turns off the sputtering power supply, then turns off the plasma power supply of the first radical supply source and supplies nitrogen gas and hydrogen gas to the vacuum chamber, then stops the supply of nitrogen gas, and after stopping the supply of nitrogen gas, controls the first radical supply source to stop the supply of hydrogen gas.

6. The film deposition apparatus according to claim 1, wherein the control unit controls the sputtering power supply to turn on the sputtering power supply when the chlorine radicals are supplied from the second radical supply source.

7. moreover, An irradiation unit provided within the vacuum chamber for irradiating the substrate with infrared light or visible light, The film deposition apparatus according to claim 1, further comprising a light-receiving unit provided in the vacuum chamber for receiving reflected light of the irradiated infrared light or visible light.

8. The substrate is positioned so as to face a target containing nitrogen and gallium in a vacuum chamber. The substrate is heated, A sputtering gas is supplied to the vacuum chamber. Nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber. A voltage is applied to the target to generate a plasma of the sputtering gas. Stop applying the voltage to the target, The supply of nitrogen radicals and hydrogen radicals to the vacuum chamber is stopped. This includes supplying chlorine radicals to the vacuum chamber, Gallium nitride produced by the recombination reaction of gallium released from the target and the nitrogen radical, and gallium nitride produced by the recombination reaction of gallium cations generated from the gallium of the target and nitrogen anions generated from the nitrogen radical are deposited on the substrate. A method for forming a gallium nitride film, comprising etching the gallium nitride formed on the substrate by the chlorine radicals.

9. The nitrogen radical and the hydrogen radical are N ２ / H ２ Mixed gas and NH ３ A method for forming a gallium nitride film according to claim 8, which is generated from any one of the gases.

10. moreover, After stopping the supply of the nitrogen radicals and the hydrogen radicals, nitrogen gas and hydrogen gas are supplied to the vacuum chamber. A method for forming a gallium nitride film according to claim 8, comprising stopping the supply of the hydrogen gas to the vacuum chamber after stopping the supply of the nitrogen gas to the vacuum chamber.

11. The chlorine radical is Cl ２ Gas and BCl ３ A method for forming a gallium nitride film according to claim 8 or claim 10, which is generated from any one of the gases.

12. Furthermore, after the chlorine radicals are supplied to the vacuum chamber, a voltage is applied to the target to generate chlorine anions. A method for forming a gallium nitride film according to claim 8 or claim 10, wherein the gallium nitride film formed on the substrate is etched with the chloride anion.

13. The method for forming a gallium nitride film according to claim 8, wherein the sputtering gas is at least one of argon and krypton.

14. The method for forming a gallium nitride film according to claim 8, wherein the substrate is one of a glass substrate and a quartz substrate.

15. The aforementioned substrate is a glass substrate, The method for forming a gallium nitride film according to claim 8, wherein the glass substrate is heated at a temperature of 400°C or higher and 600°C or lower.

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