HVPE apparatus for growing group 3 element nitride

Abstract

An HVPE apparatus for growing a group 3 element nitride, according to an embodiment of the present invention, comprises: a reactor forming a source zone in which a source metal is placed, and a growth zone for growth of a nitride single crystal; a source gas supply tube capable of supplying a gas, which contains hydrogen chloride that reacts with the source metal, to the source zone and guiding a source gas, which is generated by the reaction between the source metal and hydrogen chloride, to the growth zone; and an ammonia gas supply tube capable of supplying, to the growth zone, a gas containing ammonia, which reacts with the source gas so as to grow the nitride single crystal. At least a part of the source gas supply tube is formed from any one material from among aluminum oxide (Al2O3), pyrolytic boron nitride (PBN) and silicon carbide (SiC), or is formed from a quartz tube coated with iridium oxide (Y2O3).

Description

HVPE device for the growth of group III element nitrides

[0001] The present invention relates to a HVPE (Hydride Vapor Phase Epitaxy) device for growing a nitride of a Group III element such as gallium nitride or aluminum nitride.

[0002] III-nitride semiconductors, such as aluminum nitride (AlN) and gallium nitride (GaN), are materials with a wide energy gap and a direct transition band structure. They not only have excellent electrical properties but also have high optical transmittance in the ultraviolet or visible light range, so they are widely used in optical devices such as laser diodes (LDs) and light-emitting diodes (LEDs), as well as RF devices and power devices. These aluminum nitride and gallium nitride can be manufactured by an HVPE device that uses a hydride vapor phase epitaxy method, the so-called HVPE method.

[0003] HVPE devices use quartz tubes that have high stability and excellent chemical stability at high temperatures for the introduction of source gases and the formation of growth zones. Chlorine (HCl) gas used in HVPE devices decomposes or recombines into chlorine or chlorine radicals at high temperatures, and the chlorine or chlorine radicals decompose the quartz tube. As a result, gallium nitride or aluminum nitride substrates manufactured by conventional HVPE devices inevitably contain silicon (Si) or oxygen (O) impurities. The silicon and oxygen components of the quartz tube decomposed by chlorine radicals or chlorine are doped into gallium nitride or aluminum nitride as impurities, increasing the n-type doping concentration of gallium nitride or aluminum nitride. In the case of gallium nitride substrates manufactured by most HVPE devices using quartz tubes, the silicon concentration is 5x10 16 / cm 3 Above, the oxygen concentration is 5x10 15 / cm 3As observed above, when using a substrate containing a large amount of such impurities, electron mobility is significantly reduced due to ion scattering, and low electron mobility is the main cause of leakage current and reduced operating speed when operating gallium nitride and aluminum nitride-based electronic and power devices.

[0004] The matters described in the technical background of this invention are written to enhance understanding of the background of the invention and may include matters that are not already known in the field to which this technology belongs.

[0005] <Prior Art Literature>

[0006] - Republic of Korea Patent Publication No. 10-2018-0014456 (February 9, 2018)

[0007] - Republic of Korea Patent No. 10-2489127 (January 11, 2023)

[0008] - Republic of Korea Patent Publication No. 10-1563817 (November 9, 2015)

[0009] - Japanese Patent Publication No. 2003-012400 (January 15, 2003)

[0010] The problem to be solved by the present invention is to provide an HVPE device capable of reducing impurities contained in a Group III element nitride substrate produced.

[0011] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0012] An HVPE device for growing a Group Ⅲ element nitride according to an embodiment of the present invention includes a reactor forming a source zone in which a source metal is disposed and a growth zone for growing a nitride single crystal, a source gas supply tube configured to supply a gas containing hydrogen chloride that reacts with the source metal to the source zone and guide the source gas generated by the reaction of the source metal and the hydrogen chloride to the growth zone, and an ammonia gas supply tube configured to supply a gas containing ammonia that reacts with the source gas to grow the nitride single crystal to the growth zone. At least a portion of the source gas supply tube is formed of any one material selected from the group consisting of aluminum oxide (Al2O3), pyrolytic boron nitride (PBN), and silicon carbide (SiC), or is formed of a quartz tube coated with iridium oxide (Y2O3).

[0013] According to another embodiment of the present invention, an HVPE device may further include a cleaning gas supply tube for guiding a cleaning gas containing hydrogen chloride to suppress the growth of a poly-type nitride that parasitically grows at the end of the source gas supply tube. At least a portion of the cleaning gas supply tube may be formed of any one of aluminum oxide (Al2O3), pyrolytic boron nitride (PBN), and silicon carbide (SiC), or may be formed of a quartz tube coated with iridium oxide (Y2O3).

[0014] A method of manufacturing a Group III element nitride substrate using the HVPE device according to an embodiment of the present invention includes the steps of growing Group III element nitride to a thickness of 1 mm or more on a mother substrate placed in the growth zone by injecting a gas containing hydrogen chloride and a gas containing ammonia, separating the grown Group III element nitride from the mother substrate, slicing the separated Group III element nitride to a preset thickness to produce a Group III element nitride substrate, and surface processing the sliced ​​Group III element nitride substrate.

[0015] The Group III element nitride substrate according to the embodiment of the present invention can be manufactured by the method for manufacturing the Group III element nitride substrate described above, and has a thickness of 3x10 16 / cm 3 It has the following impurity concentrations:

[0016] The Group III element nitride substrate according to the embodiment of the present invention can be manufactured by the method for manufacturing the Group III element nitride substrate described above, and has a thickness of 700 cm 2 / It has an electron mobility of V·s or more.

[0017] The Group III element nitride substrate according to an embodiment of the present invention may be a gallium nitride substrate or an aluminum nitride substrate.

[0018] According to the present invention, by suppressing the generation of silicon and oxygen generated by the decomposition of quartz by chlorine or chlorine radicals transmitted by the use of hydrogen chloride, a nitride substrate having a low impurity concentration and thus high electron mobility can be manufactured.

[0019] In addition, various effects that can be obtained or expected due to embodiments of the present invention are disclosed directly or implicitly in the detailed description of the embodiments of the present invention.

[0020] The accompanying drawings, which are intended to aid in understanding the present invention, provide embodiments of the present invention along with a detailed description. However, the technical features of the present invention are not limited to any specific drawings, and the features disclosed in each drawing may be combined to form new embodiments. The embodiments of the present specification may be better understood by referring to the following description in conjunction with the accompanying drawings, in which similar reference numerals designate identical or functionally similar elements.

[0021] FIG. 1 is a schematic diagram showing a vertical HVPE device for growing a Group III element nitride according to an embodiment of the present invention.

[0022] FIG. 2 is a drawing schematically showing a process of a method for manufacturing a Group III element nitride substrate according to an embodiment of the present invention.

[0023] It should be understood that the drawings referenced above are not necessarily drawn to scale and are intended to provide brief representations of various features that illustrate the fundamental principles of the present invention. For example, specific design features of the present invention, including specific dimensions, orientations, positions, and shapes, will be determined in part by the specific intended application and usage environment.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the described embodiments.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "comprises" and / or "comprising," as used herein, indicate the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The term "coupled" indicates a physical relationship between two components in which the components are directly connected to one another or are indirectly connected through one or more intervening components.

[0026] In describing the components of the present invention, when it is described that a component is “connected,” “coupled,” or “connected” to another component, it should be understood that the component may be directly connected, coupled, or connected to the other component, but another component may also be “connected,” “coupled,” or “connected” between each component.

[0027] FIG. 1 is a schematic diagram of a vertical HVPE device for manufacturing a Group Ⅲ element nitride substrate according to an embodiment of the present invention. Referring to FIG. 1, a hydride vapor deposition device according to an embodiment of the present invention includes a reactor (15) forming a source zone (11) and a growth zone (13). The reactor (15) may be formed to extend vertically, and may form the source zone (11) at the top and the growth zone (13) below it. As is known, an HVPE device may be a vertical or horizontal HVPE device, and an HVPE device according to another embodiment of the present invention may be a horizontal HVPE device in which the source zone and the growth zone are arranged horizontally. Hereinafter, a vertical HVPE device will be described, but the same inventive concept may also be applied to a horizontal HVPE device.

[0028] A source metal container (17) containing a Group Ⅲ element, such as gallium (Ga) or aluminum (Al), which is a source metal, is placed in a source zone (11) within a reactor (15). For example, the source metal container (17) may have an open-topped form, and although not shown in the drawing, a source metal supply device for supplying the source metal to the source metal container (17) may be provided.

[0029] A source gas supply tube (21) configured to supply hydrogen chloride (HCl) gas for a decomposition reaction of metal gallium or aluminum is provided. As exemplarily illustrated in FIG. 1, the source gas supply tube (21) may be formed to accommodate a source metal container (17) so as to supply hydrogen chloride gas to the source metal container (17). Hydrogen chloride supplied through the source gas supply tube (21) is supplied to the source metal container (17), and at this time, nitrogen and hydrogen may be supplied together with the hydrogen chloride as shown in FIG. 1. Gallium or aluminum reacts with hydrogen chloride to produce gallium chloride (GaCl, GaCl3) or aluminum chloride (AlCl, AlCl3), which is a source gas, and the produced gallium chloride or aluminum chloride is supplied to the growth zone (13) through a downstream portion of the source gas supply tube (21).

[0030] An ammonia gas supply tube (23) is provided to supply ammonia (NH3) to the growth zone (13) for reacting with gallium chloride or aluminum chloride to produce gallium nitride or aluminum nitride. The ammonia gas supply tube (23) is configured to supply ammonia gas to the growth zone (13), and at this time, nitrogen and hydrogen can be supplied together with the ammonia as shown in FIG. 1.

[0031] A cleaning gas supply tube (25) may be further provided to supply a cleaning gas for a cleaning function to the growth zone (13). The cleaning gas may include hydrogen chloride gas, and as shown in FIG. 1, nitrogen and hydrogen may be supplied to the growth zone (13) together with the hydrogen chloride gas, which is the cleaning gas. As shown in FIG. 1, the cleaning gas supply tube (25) may be interposed between the source gas supply tube (21) and the ammonia gas supply tube (23). The cleaning gas supply tube (25) is configured to discharge a source gas, which is a mixture of hydrogen chloride, nitrogen, hydrogen, or some of these, to the end of the source gas supply tube (25), thereby suppressing the growth of poly-type gallium nitride or aluminum nitride that parasitically grows at the end of the source gas supply tube (21) through which the source gas, gallium chloride or aluminum chloride, is discharged. Additionally, hydrogen chloride and ammonia supplied to the growth zone (13) can react directly to produce ammonium chloride (NH4Cl).

[0032] Gallium chloride gas or aluminum chloride gas and ammonia gas supplied to the growth zone (13) react with each other to produce a gallium nitride single crystal or aluminum nitride single crystal film on the mother substrate (31) for growth. As a result, growth of a gallium nitride single crystal or aluminum nitride single crystal can be achieved on the mother substrate (31). For example, the mother substrate (31) may be a sapphire (Al2O3) substrate, a silicon carbide (SiC) substrate, an aluminum nitride (AlN) substrate, a gallium arsenide (GaAs) substrate, a gallium nitride (GaN) substrate, a SAM (ScAlMgO4) substrate, or a substrate on which aluminum nitride and gallium nitride are grown to a thin film thickness of 10 μm or less on such a substrate, and may be fixed to a rotating rod (33) that rotates around a longitudinal axis.

[0033] The reactor (15) may include a heating means, for example, an electric heater, capable of heating the source zone (11) and the growth zone (13) respectively so that the temperature conditions for producing gallium chloride or aluminum chloride and growing gallium nitride single crystals or aluminum nitride single crystals described above are satisfied.

[0034] Hydrogen chloride supplied through the source gas supply tube (21) or the cleaning gas supply tube (25) is used for the growth of gallium nitride or aluminum nitride or to suppress the parasitic growth of poly-type gallium nitride or aluminum nitride that grows parasitically, but the remaining hydrogen chloride is decomposed into chlorine (Cl2) and hydrogen (H2) at a high temperature, for example, 900°C or higher, and the chlorine and chlorine radicals generated in this process have strong etching properties. The HVPE device according to an embodiment of the present invention forms a tube for supplying hydrogen chloride with a material that has a low reaction rate with chlorine or chlorine radicals that have strong etching properties, taking into consideration the presence of chlorine or chlorine radicals that have strong etching properties, or a material that has a low etching rate by them.

[0035] According to an HVPE device according to an embodiment of the present invention, at least a portion of a tube through which hydrogen chloride or a mixed gas containing hydrogen chloride flows, i.e., a source gas supply tube (21) and a cleaning gas supply tube (25), is formed of a material having a low reaction rate with chlorine or chlorine radicals and a low etching rate by chlorine or chlorine radicals. The source gas supply tube (21) and the cleaning gas supply tube (25) may be formed of any one of aluminum oxide (Al2O3), pyrolytic boron nitride (PBN), and silicon carbide (SiC), or may be formed of a quartz tube coated with iridium oxide (Y2O3). By replacing quartz with such a material, the generation of silicon or oxygen due to the decomposition of quartz can be reduced, and thus, impurities in a grown gallium nitride or aluminum nitride film can be reduced. It is known that materials such as aluminum oxide have a significantly lower etching rate, or chemical reaction rate, for chlorine gas compared to silica (SiO2), the material of conventional quartz tubes. In particular, the etching rate of aluminum oxide by chlorine gas is known to be approximately 40% lower than that of silica.

[0036] Referring to FIG. 2, according to a method for manufacturing a Group Ⅲ element nitride substrate according to an embodiment of the present invention, as illustrated in (a) of FIG. 2, a mother substrate (31) is placed in a growth zone (13) of an HVPE device according to an embodiment of the present invention, and growth is performed to grow gallium nitride or aluminum nitride having a thickness of 1 mm or more on the mother substrate (31), and then, as illustrated in (b) of FIG. 2, the grown gallium nitride or aluminum nitride layer (41) is separated from the mother substrate (31) at room temperature. Then, as illustrated in (c) of FIG. 2, the separated gallium nitride or aluminum nitride layer is sliced ​​to a preset thickness to produce a gallium nitride or aluminum nitride substrate (43), and the sliced ​​gallium nitride or aluminum nitride substrate (43) is surface-polished.

[0037] The Group III element nitride substrate according to the embodiment of the present invention is 3x10 16 / cm 3 It may have the following impurity concentrations. In addition, the Group III element nitride substrate according to another embodiment of the present invention has a concentration of 700 cm 2 / It can have an electron mobility of V·s or more.

[0038] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. In an HVPE device for the growth of group Ⅲ element nitrides, A reactor that forms a source zone where a source metal is placed and a growth zone for growing a nitride single crystal, A source gas supply tube configured to supply a gas containing hydrogen chloride that reacts with the source metal to the source zone and to guide the source gas generated by the reaction of the source metal and the hydrogen chloride to the growth zone, and An ammonia gas supply tube configured to supply a gas containing ammonia that reacts with the source gas to grow the nitride single crystal to the growth zone, An HVPE device wherein at least a portion of the source gas supply tube is formed of any one of aluminum oxide (Al2O3), pyrolytic boron nitride (PBN), silicon carbide (SiC), or a quartz tube coated with iridium oxide (Y2O3).

2. In paragraph 1, Further comprising a cleaning gas supply tube for guiding a cleaning gas containing hydrogen chloride to suppress the growth of poly-type nitride parasitic growth at the end of the above source gas supply tube, An HVPE device wherein at least a portion of the cleaning gas supply tube is formed of any one of aluminum oxide (Al2O3), pyrolytic boron nitride (PBN), silicon carbide (SiC), or a quartz tube coated with iridium oxide (Y2O3).

3. In a method for manufacturing a Group III element nitride substrate using the HVPE device of paragraph 1 or 2, A step of growing a Group III element nitride to a thickness of 1 mm or more on a mother substrate placed in the growth zone by injecting a gas containing hydrogen chloride and a gas containing ammonia; A step of separating the grown Group III element nitride from the mother substrate; A step of slicing the above separated Group III element nitride to a preset thickness to produce a Group III element nitride substrate, and A method for manufacturing a group III element nitride substrate, comprising a step of surface processing the above-mentioned sliced ​​group III element nitride substrate.

4. In the Group III element nitride substrate manufactured by the method for manufacturing the Group III element nitride substrate of Article 3, The above-mentioned manufactured Group III element nitride substrate is 3x10 16 / cm 3 A group III element nitride substrate having the following impurity concentrations.

5. In paragraph 4, The above Group Ⅲ element nitride substrate is a Group Ⅲ element nitride substrate that is a gallium nitride substrate or an aluminum nitride substrate.

6. In the Group III element nitride substrate manufactured by the method for manufacturing the Group III element nitride substrate of Article 3, The above-mentioned manufactured Group III element nitride substrate is 700cm 2 Group III element nitride substrate having an electron mobility of / V·s or higher.

7. In paragraph 6, The above Group Ⅲ element nitride substrate is a Group Ⅲ element nitride substrate that is a gallium nitride substrate or an aluminum nitride substrate.

Images