Thin film deposition apparatus and method for depositing gallium nitride films

Abstract

This film formation device includes a vacuum chamber, a substrate support part that supports a substrate, a target support part that supports a target including nitrogen and gallium, a sputtering gas supply unit that supplies a sputtering gas to the vacuum chamber, a sputtering power source that applies a voltage to the target, a first radical supply source that is capable of supplying a nitrogen radical and a hydrogen radical to the vacuum chamber, and a control unit, the control unit controlling the sputtering gas supply unit, the sputtering power source, and the first radical supply source so that a first period in which the sputtering gas, the nitrogen radical, and the hydrogen radical are supplied to the vacuum chamber and a voltage is applied to the target, and a second period in which a voltage is applied to the target without the nitrogen radical and the hydrogen radical being supplied to the vacuum chamber, are repeated.

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a film deposition apparatus for depositing a gallium nitride film. Another embodiment of the present invention relates to a method for depositing a gallium nitride film. [Background technology]

[0002] In small and medium-sized display devices such as smartphones, display devices using liquid crystal displays (LCDs) and OLEDs (Organic Light Emitting Diodes) have already been commercialized. Among these, OLED display devices, which use self-emissive elements, have the advantage of high contrast and no backlight compared to liquid crystal display devices. However, because OLEDs are composed of organic compounds, it is difficult to ensure high reliability of OLED display devices due to the degradation of these organic compounds.

[0003] In recent years, development has been progressing on so-called micro-LED displays or mini-LED displays, which are next-generation display devices that incorporate tiny LED chips within the pixels of a circuit board. LEDs are self-emissive elements similar to OLEDs, but unlike OLEDs, they are composed of stable inorganic compounds containing gallium (Ga) or indium (In), making it easier to ensure high reliability in micro-LED displays compared to OLED displays. Furthermore, LED chips have high luminous efficiency, enabling high brightness. Therefore, micro-LED displays or mini-LED displays are expected to be next-generation display devices 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 project] [Problems that the invention aims to solve]

[0006] If gallium nitride films could be deposited at low temperatures, it would be possible to directly form micro-LEDs 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 in the vacuum chamber and supporting a substrate; a target support section provided in 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 for applying a voltage to the target; a first radical supply source connected to the vacuum chamber and capable of supplying nitrogen radicals and hydrogen radicals to the vacuum chamber; and a control unit that controls the sputtering gas supply section, the sputtering power supply, and the first radical supply source. The control unit controls the sputtering gas supply section, the sputtering power supply, and the first radical supply source so that a first period in which sputtering gas, nitrogen radicals, and hydrogen radicals are supplied to the vacuum chamber and a voltage is applied to the target, and a second period in which nitrogen radicals and hydrogen radicals are not supplied to the vacuum chamber and a voltage is applied to the target, are repeated.

[0009] A method for depositing a gallium nitride film according to one embodiment of the present invention involves placing a substrate facing a target containing nitrogen and gallium in a vacuum chamber, heating the substrate, supplying nitrogen radicals and hydrogen radicals to the vacuum chamber, supplying a sputtering gas to the vacuum chamber, and applying a voltage to the target to generate a sputtering gas plasma, and in a second period following the first period, supplying chlorine radicals to the vacuum chamber and applying a voltage to the target to etch the amorphous region of the gallium nitride film deposited on the substrate in the first period. [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]It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 4] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 5] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 6] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 7] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 8] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 9] It is a sequence diagram showing a control method for forming a gallium nitride film using a film forming apparatus according to an embodiment of the present invention. [Figure 10] It is a schematic diagram showing a substrate support portion of a film forming apparatus according to an embodiment of the present invention. [Figure 11] It is a schematic diagram explaining the film thickness measurement of a gallium nitride film in a film forming apparatus according to an embodiment of the present invention. [Figure 12] It is a schematic diagram showing the configuration of a light emitting device according to an embodiment of the present invention. [Figure 13] It is a flowchart showing a manufacturing method of a light emitting device according to an embodiment of the present invention. [Figure 14] It is a schematic diagram showing the configuration of a semiconductor device according to an embodiment of the present invention. [Figure 15] It is a flowchart showing a manufacturing method of a semiconductor device according to an embodiment of the present invention.

Embodiments 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," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A, B, and C, unless otherwise explicitly stated. Furthermore, these expressions do not exclude cases where α includes other elements.

[0013] In this specification, for the sake of explanation, the terms "up" or "above" or "down" or "below" will be used. However, as a general rule, the substrate on which the structure is formed is used as the reference point, and the direction from the substrate toward the structure is defined as "up" or "above." Conversely, the direction from the structure toward the substrate is defined as "down" or "below." Therefore, in the expression "structure on a substrate," the surface of the structure facing the substrate is the bottom surface of the structure, and the opposite surface is the top surface of the structure. Furthermore, the expression "structure on a substrate" merely describes the hierarchical relationship between the substrate and the structure, and other components may be placed between the substrate and the structure. In addition, the terms "up" or "above" or "down" or "below" refer to the stacking order in a structure with multiple layers, and do not necessarily mean that the layers are in a superimposed positional relationship in a plan view.

[0014] In this specification, the letters such as "1st," "2nd," or "3rd" attached to each component are merely convenient indicators used to distinguish each component, and unless otherwise specified, they have no further meaning.

[0015] In this specification and in the drawings, the same reference numeral is used to refer to multiple identical or similar components collectively, and lowercase or uppercase letters may be used to distinguish each of these components. Furthermore, hyphens and natural numbers may be used to distinguish multiple parts of a single component.

[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, provided that no technical inconsistencies arise.

[0018] <First Embodiment> Referring to Figures 1 to 9, a gallium nitride film deposition apparatus 10 according to one embodiment of the present invention will be described.

[0019] [1. Configuration of the film deposition apparatus 10] Figure 1 is a schematic diagram showing the configuration of a film deposition apparatus 10 according to one embodiment of the present invention.

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

[0021] The vacuum chamber 100 contains a substrate support section 110, a heating section 120, a target 130, and a target support section 140. The substrate support section 110 and the heating section 120 are located at the bottom of the vacuum chamber 100. The substrate is placed on the substrate support section 110. 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. The heating section 120 is located inside the substrate support section 110 and can heat the substrate placed on the substrate support section 110 to a predetermined temperature. The predetermined temperature is, for example, 400°C to 600°C. The target 130 and the target support section 140 are located at the top of the vacuum chamber 100. The target 130 is supported by the target support section 140 and is positioned to face the substrate placed on the substrate support section 110.

[0022] In Figure 1, the substrate support section 110 and heating section 120 are located at the bottom of the vacuum chamber 100, while the target 130 and target support section 140 are located at the top of the vacuum chamber 100. However, the positions of these components 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 0.5 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 through piping 151. Pump 150 can evacuate the gas inside the vacuum chamber 100 through piping 151. That is, the pump 150 connected to the vacuum chamber 100 can evacuate the gas inside the vacuum chamber 100 to a vacuum level below a predetermined level. The predetermined vacuum level is, for example, 10 -6 The pressure is in Pa, but is not limited to this. Furthermore, the pressure inside the vacuum chamber 100 can be kept constant by opening and closing the valve 152 connected to the piping 151. As the 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 frequency of 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, the voltage can be applied to the target 130 for a period of 50 μsec to 10 msec, and then the voltage can be stopped for a period of 2 μsec to 10 msec. In the film deposition apparatus 10 according to this embodiment, a gallium nitride film is deposited by repeatedly alternating between periods in which a voltage is applied to the target 130 and periods in which the voltage is stopped from being applied to the target 130. 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 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 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 from the first radical supply source 180 to the vacuum chamber 100.

[0036] The first gas may not be an N2 / H2 mixed gas, but rather a gas supplied separately as nitrogen gas (N2 gas) and hydrogen gas (H2 gas). In this case, the control unit 200 can independently control the start or stop of the supply of N2 gas and H2 gas.

[0037] 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.

[0038] As described above, the control unit 200 can control the first plasma power supply 182 and the first gas supply unit 183, but the control unit 200 also controls the start or stop of the supply of the first radical from the first radical supply source 180. For convenience, in the following, the control unit 200 may be described as controlling the first radical supply source 180. Similarly, the control unit 200 may be described as controlling the second radical supply source 190.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] [2. Method for forming a gallium nitride film using the film deposition apparatus 10] The film deposition apparatus 10, controlled by the control unit 200, enables various methods for depositing gallium nitride films. Several examples of control methods for depositing gallium nitride films are described below. However, the deposition of gallium nitride films using the film deposition apparatus 10 is not limited to the following control methods.

[0043] [2-1. Control Method 1] Figure 3 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0044] The control method shown in Figure 3 includes a first period from time t1 to time t8 and a second period from time t9 to time t12. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0045] At time t1, the supply of N2 / H2 mixed gas from the first gas supply unit 183 begins. At time t2, the first plasma power supply 182 is turned on, and nitrogen radicals and hydrogen radicals are generated from the supplied N2 / H2 mixed gas. The generated nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber 100.

[0046] At time t3, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. The flow rate of Ar gas is adjusted by the mass flow controller 172 so that the pressure inside the vacuum chamber 100 reaches a predetermined pressure. The predetermined pressure is, for example, 0.1 Pa or more and 10 Pa or less. At time t4, the sputtering power supply 160 is turned on and sputtering begins. Specifically, the Ar gas supplied to the vacuum chamber 100 is plasma-formed, and argon cations (Ar) are produced. + ) and electrons (e - Argon cations are generated. The argon cations 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.

[0047] At time t5, the sputtering power supply 160 is turned off, and sputtering stops. At time t6, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped.

[0048] At time t7, the first plasma power supply 182 is turned off, and the supply of nitrogen radicals and hydrogen radicals to the vacuum chamber 100 is stopped. At time t8, the supply of N2 / H2 mixed gas from the first gas supply unit 183 is stopped.

[0049] At time t9, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. At time t10, the sputtering power supply 160 is turned on, and sputtering begins.

[0050] At time t11, the sputtering power supply 160 is turned off, and sputtering stops. At time t12, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped.

[0051] Gallium nitride has two crystal axes: a gallium plane with Ga polarity (hereinafter referred to as the "Ga plane") and a nitrogen plane with N polarity (hereinafter referred to as the "N plane"). The Ga plane is chemically stable but thermally unstable. On the other hand, the N plane is thermally stable but chemically unstable. The control method shown in Figure 3 allows the surface of a gallium nitride film to be controlled to be either the Ga plane or the N plane.

[0052] During the first period, from time t4 to time t5, the vacuum chamber 100 contains not only gallium and gallium cations generated by sputtering, but also nitrogen radicals supplied from the first radical source 180. Therefore, the gallium recombines with the nitrogen radicals to produce gallium nitride. The generated gallium nitride is deposited on the substrate, forming a gallium nitride film.

[0053] Furthermore, during the first period from time t4 to time t5, 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 produced nitrogen anions recombine with gallium cations present near the substrate to produce gallium nitride. The produced 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.

[0054] Furthermore, during the first period from time t5 to time t8, gallium nitride is produced by yet another recombination reaction. Specifically, during the first period from time t5 to time t8, gallium nitride can be produced by utilizing the metastable state of Ar gas. Here, we will explain the production of gallium nitride using the metastable state of Ar gas.

[0055] 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. That is, metastable argon atoms can persist even after the application of voltage to the target 130 is stopped.

[0056] 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 collision is 9.756 eV, which is close to the metastable state energy of argon atoms. Therefore, when nitrogen molecules collide with metastable argon atoms, a dissociation reaction of 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 atoms. As mentioned above, nitrogen has high electronegativity, so nitrogen radicals react with electrons in the vacuum chamber 100 to produce nitrogen anions. Also, between times t6 and t7, 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. These 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.

[0057] As described above, in the first period, the gallium nitride film is deposited even when the sputtering power supply is off, thus improving the deposition rate of the gallium nitride film in the deposition apparatus 10. Furthermore, all of the recombination reactions described above are carried out under a sufficient nitrogen atmosphere. As a result, an N-plane is formed on the surface of the gallium nitride film deposited in the first period.

[0058] 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 the first period, hydrogen radicals are supplied to the vacuum chamber 100. The 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.

[0059] 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.

[0060] During the second period, from time t10 to time t11, gallium and gallium cations generated by sputtering, as well as nitrogen and nitrogen anions released from target 130, are present in the vacuum chamber 100. Therefore, the gallium and gallium cations recombine with the nitrogen and nitrogen anions to produce gallium nitride. The generated gallium nitride is deposited on the substrate, forming a gallium nitride film.

[0061] During the second period, nitrogen radicals are not supplied to the vacuum chamber 100. Preferably, the composition of the gallium nitride target 130 is such that there is more gallium than nitrogen. Therefore, a Ga surface is formed on the surface of the gallium nitride film deposited during the second period. However, even after the supply of nitrogen radicals is stopped, unwanted gas may remain in the vacuum chamber 100. In that case, it is preferable to set the second period taking into account the time required to evacuate the gas from the vacuum chamber 100.

[0062] As explained above, the control method shown in Figure 3 allows for the formation of a high-quality gallium nitride film by controlling the surface of the gallium nitride film to either the Ga or N plane.

[0063] [2-2. Control Method 2] Figure 4 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0064] The control method shown in Figure 4 includes a first period from time t1 to time t8 and a second period from time t9 to time t16. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0065] The first period is the same as the first period of control method 1 described above, so its explanation is omitted here.

[0066] At time t9, the supply of Cl2 gas from the second gas supply unit 193 begins. At time t10, the second plasma power supply 192 is turned on, and chlorine radicals are generated from the supplied Cl2 gas. The generated chlorine radicals are supplied to the vacuum chamber 100.

[0067] At time t11, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. At time t12, the sputtering power supply 160 is turned on, and sputtering begins.

[0068] At time t13, the sputtering power supply 160 is turned off, and sputtering stops. At time t14, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped.

[0069] At time t15, the second plasma power supply 192 is turned off, and the supply of chlorine radicals to the vacuum chamber 100 is stopped. At time t16, the supply of Cl2 gas from the second gas supply unit 193 is stopped.

[0070] The gallium nitride film deposited in the first period includes not only crystalline regions but also amorphous regions. Therefore, in the second period, chlorine radicals are used to etch the amorphous regions of the gallium nitride film. This etching can improve 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. Near the substrate heated above 400°C, gallium chloride is a gas, and gallium nitride is not deposited on the substrate.

[0071] During the second period, from time t12 to t13, sputtering is performed, and the chlorine radicals supplied to the vacuum chamber 100 are 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. Consequently, during the second period, from time t12 to t13, not only chlorine radicals but also chlorine anions can be used to efficiently etch the amorphous regions of the gallium nitride film.

[0072] Furthermore, during the second period, a gallium nitride film is deposited on the substrate, and a Ga surface is formed on the surface of the gallium nitride film deposited during the second period.

[0073] Although chlorine may remain in the vacuum chamber 100 after the second period, hydrogen radicals supplied to the vacuum chamber 100 react with chlorine during the first period following the second period to produce hydrogen chloride. The generated hydrogen chloride is then exhausted from the vacuum chamber 100 by a pump, thereby reducing the amount of residual chlorine in the vacuum chamber 100 or the gallium nitride film.

[0074] As explained above, the control method shown in Figure 4 allows for the formation of a high-quality gallium nitride film by controlling the surface of the gallium nitride film to either the Ga or N plane, while simultaneously etching the amorphous regions.

[0075] [2-3. Control Method 3] Figure 5 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0076] The control method shown in Figure 5 includes a first period from time t1 to time t8 and a second period from time t9 to time t14. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support section 110.

[0077] The first period is the same as the first period of control method 1 described above, so its explanation is omitted here.

[0078] At time t9, the supply of Cl2 gas from the second gas supply unit 193 begins. At time t10, the second plasma power supply 192 is turned on, and chlorine radicals are generated from the supplied Cl2 gas. The generated chlorine radicals are supplied to the vacuum chamber 100.

[0079] At time t11, the sputtering power supply 160 is turned ON. At time t12, the sputtering power supply 160 is turned OFF.

[0080] At time t13, the second plasma power supply 192 is turned off, and the supply of chlorine radicals to the vacuum chamber 100 is stopped. At time t14, the supply of Cl2 gas from the second gas supply unit 193 is stopped.

[0081] In the second period, Ar gas is not supplied, and sputtering does not occur. On the other hand, because Ar gas is not supplied to the vacuum chamber 100, the number of chlorine radicals relative to the total number of particles in the vacuum chamber increases, which can promote etching of the amorphous region of the gallium nitride film by chlorine radicals. In addition, during etching of the amorphous region, the surface of the gallium nitride film changes from the chemically unstable N plane to the chemically stable Ga plane.

[0082] As explained above, the control method shown in Figure 5 allows for the formation of a high-quality gallium nitride film by controlling the surface of the gallium nitride film to either the Ga or N plane, while simultaneously etching the amorphous regions.

[0083] [2-4. Control Method 4] Figure 6 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0084] The control method shown in Figure 6 includes a first period from time t1 to time t10 and a second period from time t11 to time t18. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0085] At time t1, the supply of H2 from the first gas supply unit 183 begins. At time t2, the first plasma power supply 182 is turned on, and hydrogen radicals are generated from the supplied H2 gas. The generated hydrogen radicals are supplied to the vacuum chamber 100. At time t3, the supply of N2 gas from the first gas supply unit 183 begins. At this time, since the first plasma power supply 182 is turned on, nitrogen radicals are generated from the supplied N2 gas. The generated nitrogen radicals are supplied to the vacuum chamber 100.

[0086] At time t4, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. At time t5, the sputtering power supply 160 is turned on, and sputtering begins.

[0087] At time t6, the sputtering power supply 160 is turned off, and sputtering stops. At time t7, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped.

[0088] At time t8, the supply of N2 gas from the first gas supply unit 183 is stopped. As a result, the generation of nitrogen radicals in the first radical supply source 180 is stopped, and the supply of nitrogen radicals to the vacuum chamber 100 is also stopped. At time t9, the first plasma power supply 182 is turned off, and the supply of hydrogen radicals to the vacuum chamber 100 is stopped. At time t10, the supply of H2 gas from the first gas supply unit 183 is stopped.

[0089] Since the time intervals t11 to t18 are the same as those t9 to t16 in control method 2 described above, we will omit the explanation here.

[0090] During the first period, at times t1-t2 and t8-t9, only hydrogen radicals are supplied to the vacuum chamber 100. In other words, during the first period, only hydrogen radicals are supplied to the vacuum chamber 100 before and after the deposition of the gallium nitride film. As described above, hydrogen radicals have the effect of reducing residual oxygen in the vacuum chamber 100, and furthermore, they can remove gallium oxide formed on the surface of the gallium nitride film immediately before or immediately after deposition.

[0091] As explained above, the control method shown in Figure 6 allows for the formation of a high-quality gallium nitride film by controlling the surface of the gallium nitride film to either the Ga or N plane, and by removing the gallium oxide formed on the surface of the gallium nitride film.

[0092] [2-5. Control Method 5] Figure 7 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0093] The control method shown in Figure 7 includes a first period from time t1 to time t10 and a second period from time t11 to time t18. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0094] At time t1, the supply of N2 from the first gas supply unit 183 begins. At time t2, the first plasma power supply 182 is turned on, and nitrogen radicals are generated from the supplied N2 gas. The generated nitrogen radicals are supplied to the vacuum chamber 100. At time t3, the supply of H2 gas from the first gas supply unit 183 begins. At this time, since the first plasma power supply 182 is turned on, hydrogen radicals are generated from the supplied H2 gas. The generated hydrogen radicals are supplied to the vacuum chamber 100.

[0095] At time t4, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 begins. At time t5, the sputtering power supply 160 is turned on, and sputtering begins.

[0096] At time t6, the sputtering power supply 160 is turned off, and sputtering stops. At time t7, the supply of Ar gas from the sputtering gas supply unit 170 to the vacuum chamber 100 is stopped.

[0097] At time t8, the supply of H2 gas from the first gas supply unit 183 is stopped. As a result, the generation of hydrogen radicals in the first radical supply source 180 is stopped, and the supply of hydrogen radicals to the vacuum chamber 100 is also stopped. At time t9, the first plasma power supply 182 is turned off, and the supply of nitrogen radicals to the vacuum chamber 100 is stopped. At time t10, the supply of N2 gas from the first gas supply unit 183 is stopped.

[0098] Since the time intervals t11 to t18 are the same as those t9 to t16 in control method 2 described above, we will omit the explanation here.

[0099] During the first period, at times t1-t2 and t8-t9, only nitrogen radicals are supplied to the vacuum chamber 100. In other words, during the first period, only nitrogen radicals are supplied to the vacuum chamber 100 before and after the deposition of the gallium nitride film. As a result, nitriding of the surface of the gallium nitride film is promoted, and the formation of the N-plane of the gallium nitride film can be stabilized.

[0100] As explained above, the control method shown in Figure 7 allows for the control of the gallium nitride film's surface to either the Ga or N plane, while also stabilizing the N plane of the gallium nitride film, thereby enabling the formation of a high-quality gallium nitride film.

[0101] [2-6. Control Method 6] Figure 8 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0102] The control method shown in Figure 8 includes a first period from time t1 to time t10 and a second period from time t11 to time t16. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0103] Since the time intervals t1 to t10 are the same as those in control method 4 described above, we will omit their explanation here.

[0104] Since the time intervals t11 to t16 are the same as the time intervals t9 to t14 in control method 3 described above, we will omit the explanation here.

[0105] As explained above, the control method shown in Figure 8 controls the surface of the gallium nitride film to either the Ga or N plane. Furthermore, by etching the amorphous region and removing the gallium oxide formed on the surface of the gallium nitride film, a high-quality gallium nitride film can be deposited.

[0106] [2-7. Control Method 7] Figure 9 is a sequence diagram showing a control method for depositing a gallium nitride film using a film deposition apparatus 10 according to one embodiment of the present invention.

[0107] The control method shown in Figure 9 includes a first period from time t1 to time t10 and a second period from time t11 to time t16. In the film deposition apparatus 10, the first period and the second period are repeated, thereby depositing a gallium nitride film on the substrate placed on the substrate support 110.

[0108] Since the time intervals t1 to t10 are the same as those in control method 5 described above, their explanation is omitted here.

[0109] Since the time intervals t11 to t16 are the same as the time intervals t9 to t14 in control method 3 described above, we will omit the explanation here.

[0110] As explained above, the control method shown in Figure 9 controls the surface of the gallium nitride film to either the Ga plane or the N plane. Furthermore, by etching the amorphous region and stabilizing the N plane of the gallium nitride film, a high-quality gallium nitride film can be formed.

[0111] As described above, the film deposition apparatus 10 according to this embodiment can deposit a high-quality gallium nitride film at a low temperature without raising the substrate temperature. Therefore, by using the film deposition apparatus 10, a high-quality gallium nitride film can be deposited on substrates with low heat resistance, such as glass substrates.

[0112] <Second Embodiment> Referring to Figures 10 and 11, 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 description, configurations similar to those described in the first embodiment may be omitted.

[0113] Figure 10 is a schematic diagram showing the substrate support portion 110A of a film deposition apparatus 10 according to one embodiment of the present invention.

[0114] As shown in Figure 10, the film deposition apparatus 10 is equipped with an irradiation unit 111A that irradiates light onto a substrate 510 placed on a 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.

[0115] Figure 11 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.

[0116] As described in the first 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 510.

[0117] 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.

[0118] 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.

[0119] <Third Embodiment> A light-emitting element 1000 according to one embodiment of the present invention will be described with reference to Figures 12 and 13.

[0120] [1. Configuration of the light-emitting element 1000] Figure 12 is a schematic diagram showing the configuration of a light-emitting element 1000 according to one embodiment of the present invention.

[0121] As shown in Figure 12, the light-emitting element 1000 includes a substrate 1010, a compensation layer 1020, a buffer layer 1030, an undoped semiconductor layer 1035, an n-type semiconductor layer 1040, a light-emitting layer 1050, a p-type semiconductor layer 1060, a protective layer 1070, an n-type electrode 1080, and a p-type electrode 1090. The light-emitting element 1000 is a so-called LED (Light Emitting Diode), but is not limited to this.

[0122] For example, a glass substrate or a quartz substrate can be used as the substrate 1010. Since a gallium nitride film can be formed at low temperatures using the film deposition apparatus 10, it is preferable to use a glass substrate that allows for large-area deposition as the substrate 1010. The glass substrate is an amorphous substrate composed of a glass material that generally lacks a crystalline structure but has a crystalline structure in trace areas. The upper limit of the thermal expansion coefficient of the glass substrate is 4.2 × 10⁻⁶. -6 Less than / K, preferably 4.0 × 10 -6 It is less than / K. The lower limit of the thermal expansion coefficient of the glass substrate is 3.0 × 10⁻⁶. -6 Exceeding / K, preferably 3.5 × 10 -6 The temperature exceeds / K. The glass substrate must be resistant to the thermal history during semiconductor device fabrication. Therefore, the lower limit of the glass transition temperature of the glass substrate is, for example, 650°C or higher, preferably 720°C or higher. The upper limit of the glass transition temperature of the glass substrate is, for example, 900°C or lower, preferably 810°C or lower. For similar reasons, the lower limit of the softening point of the glass substrate is, for example, 900°C or higher, preferably 950°C or higher. The upper limit of the softening point of the glass substrate is, for example, 1150°C or lower, preferably 1050°C or lower.

[0123] To prevent contamination of the light-emitting layer 1050 by alkali metal components generated from the glass material, glass materials with a low alkali metal content can be used as the glass substrate. For example, the alkali metal content in the glass substrate is 0.1% by mass or less.

[0124] As such a glass substrate, for example, amorphous glass material composed of aluminoborosilicate glass or aluminosilicate glass is used. Such amorphous glass materials are used in liquid crystal displays and organic electroluminescent (OLED) displays, and large-area glass substrates called mother glass are available on the market. By selecting a glass substrate as the substrate for the light-emitting element 1000, the light-emitting element 1000 can be manufactured at low cost using a large-area substrate.

[0125] The substrate 1010 has a first surface on which the light-emitting layer 1050 is formed, and a second surface on which the compensation layer 1020 is formed. The surface roughness of the first surface and the second surface of the substrate 1010 do not have to be the same. However, from the viewpoint of preventing electrostatic discharge damage due to peeling charge when removing the light-emitting element 1000 from various devices during the manufacturing process, the surface roughness of the second surface can be made rougher than the surface roughness of the first surface.

[0126] The thickness of the substrate 1010 is not particularly limited, but from the viewpoint of reducing warping, a substrate that is sufficiently thicker than the total film thickness of the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060 can be used. For example, the substrate 1010 has a film thickness of 50 times or more the total film thickness of the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060. The substrate 1010 has a thickness of, for example, 0.5 to 1.0 mm.

[0127] The mechanical strength of the substrate 1010 is not particularly limited, but from the viewpoint of reducing warping, it is preferable to have, for example, a Young's modulus of 70 to 90 GPa.

[0128] The compensation layer 1020 is formed on the second surface of the substrate 1010. By providing the compensation layer 1020, it is possible to reduce the warping of the substrate that is disadvantageous during the fabrication of the light-emitting element 1000. Further, when forming the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060 under reduced pressure and heating, the presence of the compensation layer 1020 on the second surface can reduce outgassing such as H2O from the second surface side of the substrate 1010, and reduce oxygen contamination in the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060. Further, by appropriately selecting the material of the compensation layer 1020, the resistance to chemical solution treatment with an acid used in the fabrication process of the light-emitting element 1000 can also be improved.

[0129] By setting the coefficient of thermal expansion of the compensation layer 1020 within a predetermined range, it is possible to relieve the warping of the substrate 1010 caused by the difference in the coefficient of thermal expansion between the substrate 1010 and the n-type semiconductor layer 1040, the light-emitting layer 1050, or the p-type semiconductor layer 1060. The coefficient of thermal expansion of the compensation layer 1020 is larger than that of the substrate 1010 and smaller than the coefficients of thermal expansion of the substrate 1010, the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060. The lower limit of the coefficient of thermal expansion of the compensation layer 1020 is, for example, more than 4.0×10 -6 / K, preferably more than 4.1×10 -6 / K. Also, the upper limit of the coefficient of thermal expansion of the compensation layer 1020 is, for example, less than 5.0×10 -6 / K, preferably less than 4.6×10 -6 / K.

[0130] Since the compensation layer 1020 is adjacent to the substrate 1010, by setting the thermal conductivity to a predetermined value, in the heating process of forming the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060 on the substrate 1010, heat can be efficiently and evenly transferred to the entire substrate, and as a result, the uniformity of the film thickness of the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060 can also be improved. Therefore, the compensation layer 1020 can have a thermal conductivity that exceeds that of the substrate 1010. The thermal conductivity of the compensation layer 1020 can be appropriately set according to the material constituting the substrate 1010. For example, 10W·m-1 ·K -1 Exceeding 40W·m, preferably 40W·m -1 ·K -1 It exceeds.

[0131] The thermal conductivity of the compensation layer 1020 can be adjusted by adjusting the film density to a predetermined value. The relationship between film density and thermal conductivity varies depending on the material constituting the compensation layer 1020, but the lower limit of the film density of the compensation layer 1020 is, for example, 2.50 g / cm³. 3 The above is preferable, preferably 2.60 g / cm³. 3 That concludes the explanation. Furthermore, the upper limit of the film density of compensation layer 1020 is 4.10 g / cm³. 3 The following, preferably 4.00 g / cm³ 3 The following applies:

[0132] The material used for the compensation layer 1020 is not particularly limited as long as it satisfies the aforementioned physical properties, but it is preferable that it has resistance to chemical treatment with acids, etc., used in the manufacturing process of the light-emitting element 1000. For example, an aluminum nitride film or an aluminum oxide film, or a laminated film of an aluminum nitride film and an aluminum oxide film can be used as the compensation layer 1020.

[0133] The method for forming the compensation layer 1020 is not particularly limited, and known film deposition methods can be used. However, in order to form the compensation layer 1020 on a large-area substrate and to prevent the temperature of the substrate 1010 from rising excessively during the formation of the compensation layer 1020, it is preferable to form the compensation layer 1020 by sputtering. The sputtering conditions are not particularly limited, and known sputtering equipment can be used, with the conditions set as appropriate.

[0134] The thickness of the compensation layer 1020 is not particularly limited and is set appropriately according to the structure of the light-emitting element 1000. However, from the viewpoint of reducing warping of the substrate 1010, it can be formed so as not to be excessively thin compared to the total thickness of the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060. For example, the compensation layer 1020 can have a thickness of 80% or more of the total thickness of the n-type semiconductor layer 1040, the light-emitting layer 1050, and the p-type semiconductor layer 1060.

[0135] The buffer layer 1030 can control the crystal orientation of the undoped semiconductor layer 1035 and the n-type semiconductor layer 1040, thereby improving the crystallinity of the n-type semiconductor layer 1040. For example, an aluminum nitride film can be used as the buffer layer 1030.

[0136] The undoped semiconductor layer 1035 can promote the epitaxial growth of the n-type semiconductor layer 1040. For example, a gallium nitride film can be used as the undoped semiconductor layer 1035.

[0137] 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 protective layer 1070, a silicon oxide film can be used. As the n-type electrode 1080, a metal film such as indium can be used. As the p-type electrode 1090, a metal film such as palladium or gold can be used. Note that the oxygen concentration in the light-emitting layer 1050 and the p-type semiconductor layer 1060 is 1 × 10⁻¹⁶. 18 cm -3 It is preferable that it be less than [a certain value].

[0138] [2. Method for fabricating the light-emitting element 1000] Figure 13 is a flowchart showing a method for manufacturing a light-emitting element 1000 according to one embodiment of the present invention.

[0139] In step S1000, an aluminum nitride film is deposited on the second surface of the substrate 1010 as a compensation layer 1020. The aluminum nitride film can be deposited using the deposition apparatus 10 or another sputtering apparatus. When using the deposition apparatus 10, nitrogen radicals and hydrogen radicals may be supplied from the first radical supply source 180.

[0140] In step S1010, an aluminum nitride film is deposited on the first surface of the substrate 1010 as a buffer layer 1030. The aluminum nitride film can be deposited using the deposition apparatus 10 or another sputtering apparatus. When using the deposition apparatus 10, nitrogen radicals and hydrogen radicals may be supplied from the first radical supply source 180.

[0141] In step S1020, a gallium nitride film is deposited on the buffer layer 1030 as an undoped semiconductor layer 1035. The gallium nitride film can be deposited using the deposition apparatus 10.

[0142] In step S1030, a silicon-doped gallium nitride film is deposited on the undoped semiconductor layer 1035 as an n-type semiconductor layer 1040. The silicon-doped gallium nitride film can be deposited using the deposition apparatus 10. Specifically, silicon-doped gallium nitride is used as the target 130, and sputtering is performed while supplying nitrogen radicals and hydrogen radicals from the first radical supply source 180.

[0143] In step S1040, an indium gallium nitride film and a gallium nitride film are alternately deposited on the n-type semiconductor layer 1040 as an emissive layer 1050. The indium gallium nitride film and the gallium nitride film can be deposited using the deposition apparatus 10. In the deposition of the indium gallium nitride film, indium gallium nitride is used as the target 130, and sputtering is performed while supplying nitrogen radicals and hydrogen radicals from the first radical supply source 180.

[0144] In step S1050, a magnesium-doped gallium nitride film is deposited on the light-emitting layer 1050 as a p-type semiconductor layer 1060. The magnesium-doped gallium nitride film can be deposited using the deposition apparatus 10. Specifically, magnesium-doped gallium nitride is used as the target 130, and sputtering is performed while supplying nitrogen radicals and hydrogen radicals from the first radical supply source 180.

[0145] In step S1060, heat treatment is performed. In some cases, the activation rate of magnesium added to the gallium nitride film in step S1050 may be low. In such cases, heat treatment can be performed to activate the magnesium and enable it to function as a p-type semiconductor layer 1060.

[0146] In step S1070, the p-type semiconductor layer 1060, the light-emitting layer 1050, and the n-type semiconductor layer 1040 are etched into a predetermined pattern using photolithography. The n-type semiconductor layer 1040 is etched in such a way that its surface is exposed (i.e., a portion of the n-type semiconductor layer 1040 remains). For etching, for example, plasma etching can be used.

[0147] In step S1080, a silicon oxide film is deposited as a protective layer 1070 so as to cover the surface of the p-type semiconductor layer 1060, the exposed surface of the n-type semiconductor layer 1040, and the sides of each layer. The silicon oxide film can be deposited using a CVD apparatus.

[0148] In step S1090, the protective layer 1070 is patterned using photolithography so that openings are formed that expose the surface of the p-type semiconductor layer 1060 and the surface of the n-type semiconductor layer 1040.

[0149] In step S1100, a Ti / Al / Ti / Au metal multilayer film is formed on the n-type semiconductor layer 1040 through an opening as an n-type electrode 1080.

[0150] In step S1110, a Ni / Au metal multilayer film is formed on the p-type semiconductor layer 1060 as a p-type electrode 1090 through an opening.

[0151] In step S1120, heat treatment is performed. This reduces the contact resistance between the n-type semiconductor layer 1040 and the n-type electrode 1080, and between the p-type semiconductor layer 1060 and the p-type electrode 1090.

[0152] 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.

[0153] <Fourth Embodiment> Referring to Figures 14 and 15, a semiconductor device 2000 according to one embodiment of the present invention will be described.

[0154] [1. Configuration of Semiconductor Device 2000] Figure 14 is a schematic diagram showing the configuration of semiconductor device 2000 according to one embodiment of the present invention.

[0155] As shown in Figure 13, the semiconductor device 2000 includes a substrate 2010, a compensation layer 2020, a buffer layer 2030, a semiconductor layer 2040, a gate insulating layer 2050, a gate electrode 2060, a source electrode 2070, and a drain electrode 2080. The semiconductor device 2000 is a so-called transistor, but is not limited to that.

[0156] Since the substrate 2010, compensation layer 2020, and buffer layer 2030 are the same as those of the substrate 1010, compensation layer 1020, and buffer layer 1030 of the third embodiment, respectively, their description is omitted here.

[0157] For example, a silicon-doped gallium nitride film (n-type gallium nitride semiconductor film) or a gallium nitride film (undopulated gallium nitride semiconductor film) can be used as the semiconductor layer 2040. The gate insulating layer 2050 can be a silicon oxide film or a silicon nitride film, etc. For the gate electrode 2060, source electrode 2070, and drain electrode 2080, metal films such as aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), silver (Ag), palladium (Pd), and indium (In), or multilayer metal films thereof, can be used.

[0158] [2. Method for fabricating semiconductor device 2000] Figure 15 is a flowchart showing a method for fabricating a semiconductor device according to one embodiment of the present invention.

[0159] In step S2000, an aluminum nitride film is deposited on the second surface of the substrate 2010 as a compensation layer 2020. The aluminum nitride film can be deposited using the deposition apparatus 10 or another sputtering apparatus. When using the deposition apparatus 10, nitrogen radicals and hydrogen radicals may be supplied from the first radical supply source 180.

[0160] In step S2010, an aluminum nitride film is deposited on the first surface of the substrate 2010 as a buffer layer 2030. The aluminum nitride film can be deposited using the deposition apparatus 10 or another sputtering apparatus. When using the deposition apparatus 10, nitrogen radicals and hydrogen radicals may be supplied from the first radical supply source 180.

[0161] In step S2020, a gallium nitride film is deposited on the buffer layer 2030 as a semiconductor layer 2040. The gallium nitride film can be deposited using the deposition apparatus 10.

[0162] In step S2030, a silicon oxide film is deposited on the semiconductor layer 2040 as a gate insulating layer 2050. The silicon oxide film can be deposited using a CVD apparatus.

[0163] In step S2040, the gate insulating layer 2050 and the semiconductor layer 2040 are patterned using photolithography. The gate insulating layer 2050 is patterned so that the surface of the semiconductor layer 2040 is exposed. The semiconductor layer 2040 is patterned in an island pattern.

[0164] In step S2050, a Ti / Al multilayer metal film is formed on the gate insulating layer 2050 as the gate electrode 2060. Additionally, a Ti / Al multilayer metal film is formed on the exposed surface of the semiconductor layer 2040 as the source electrode 2070 and the drain electrode 2080.

[0165] In step S2060, heat treatment is performed. This reduces the contact resistance between the semiconductor layer 2040 and the source electrode 2070, and between the semiconductor layer 2040 and the drain electrode 2080.

[0166] 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.

[0167] 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.

[0168] 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]

[0169] 10: Film deposition apparatus, 100: Vacuum chamber, 110, 110A: 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: Compensation layer, 1030: Buffer layer, 1035: Undoped semiconductor layer, 1040: n-type semiconductor layer, 1050: Light-emitting layer, 1060: p-type semiconductor layer, 1070: Protective layer, 1080: n-type electrode, 1090: p-type electrode, 2000: Semiconductor element, 2010: Substrate, 2020: Compensation layer, 2030: Buffer layer, 2040: Semiconductor layer, 2050: Gate insulating layer, 2060: Gate electrode, 2070: Source electrode, 2080: Drain 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 for applying voltage to the target, A first radical supply source connected to the vacuum chamber and capable of supplying nitrogen radicals and hydrogen radicals to the vacuum chamber, The system includes the sputtering gas supply unit, the sputtering power supply, and a control unit for controlling the first radical supply source, A film deposition apparatus, wherein the control unit controls the sputtering gas supply unit, the sputtering power supply, and the first radical supply source so as to repeat a first period in which the sputtering gas, the nitrogen radicals, and the hydrogen radicals are supplied to the vacuum chamber, a voltage is applied to the target, and then the application of the voltage to the target is stopped; and a second period in which the nitrogen radicals and the hydrogen radicals are not supplied to the vacuum chamber, a voltage is applied to the target, and then the application of the voltage to the target is stopped.

2. The film deposition apparatus according to claim 1, wherein the sputtering gas is supplied during the second period.

3. The film deposition apparatus according to claim 1, wherein, in the first period, the supply of the nitrogen radical and the hydrogen radical is started, and then the supply of the sputtering gas is started.

4. The film deposition apparatus according to claim 3, wherein, in the first period, after the supply of the sputtering gas is stopped, the supply of the nitrogen radical and the hydrogen radical is stopped.

5. Furthermore, it includes a second radical source connected to the vacuum chamber and capable of supplying chlorine radicals to the vacuum chamber, The control unit further controls the second radical supply source, The film deposition apparatus according to claim 1, wherein the chlorine radical is supplied during the second period.

6. The film deposition apparatus according to claim 5, wherein the sputtering gas is supplied during the second period.

7. The film deposition apparatus according to claim 5, wherein, in the first period, the supply of the nitrogen radical and the hydrogen radical is started, and then the supply of the sputtering gas is started.

8. The film deposition apparatus according to claim 7, wherein, in the first period, the supply of the hydrogen radical is started, and then the supply of the nitrogen radical is started.

9. The film deposition apparatus according to claim 7, wherein, in the first period, the supply of hydrogen radicals is started after the supply of nitrogen radicals is started.

10. The film deposition apparatus according to claim 7, wherein, in the first period, after the supply of the sputtering gas is stopped, the supply of the nitrogen radical and the hydrogen radical is stopped.

11. The film deposition apparatus according to claim 10, wherein, in the first period, the supply of the hydrogen radical is stopped, and then the supply of the nitrogen radical is stopped.

12. The film deposition apparatus according to claim 11, wherein, in the first period, the supply of the nitrogen radical is stopped, and then the supply of the hydrogen radical is stopped.

13. The substrate is placed so as to face a target containing nitrogen and gallium in a vacuum chamber. The substrate is heated, In the first period, Nitrogen radicals and hydrogen radicals are supplied to the vacuum chamber. A sputtering gas is supplied to the vacuum chamber. By applying a voltage to the target, a plasma of the sputtering gas is generated. Stop applying voltage to the target, In the second period following the first period, A chlorine radical is supplied to the vacuum chamber. By applying a voltage to the target, the amorphous region of the gallium nitride film deposited on the substrate during the first period is etched. A method for forming a gallium nitride film, wherein the application of voltage to the target is stopped.

14. The method for forming a gallium nitride film according to claim 13, further comprising supplying the sputtering gas to the vacuum chamber during the second period.

15. The aforementioned substrate is a glass substrate, The method for forming a gallium nitride film according to claim 13, wherein the glass substrate is heated at a temperature of 400°C or higher and 600°C or lower.

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