KR20200125073A - A Hydride Vapor Phase Epitaxy Apparatus for Manufacturing a GaN Wafer and a Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a hydride vapor phase epitaxy (HVPE) apparatus for manufacturing a GaN wafer and a GaN wafer manufacturing method by the same to grow a nitride semiconductor single-crystal wafer such as a nitride GaN wafer by a vapor growth method. The HVPE apparatus for manufacturing a GaN wafer comprises: a main tube (11); a reactor chamber (12) for GaN nitride semiconductor single-crystal growth arranged on the main tube (11); a first heating furnace (14a) installed on the circumferential surface of the main tube (11) to heat a semiconductor material of a source area; and a second heating furnace (14b) installed on the circumferential surface of the main tube (11) to heat at a higher temperature than the first heating surface (14a). A growth area heated by the second heating furnace (14b) is protected by a material which limits generation of Si or O.

Description

HVPE device for manufacturing a GaN wafer and a method for manufacturing a GaN wafer therefrom {A Hydride Vapor Phase Epitaxy Apparatus for Manufacturing a GaN Wafer and a Method for Manufacturing the Same}

The present invention relates to an HVPE apparatus for manufacturing a GaN wafer for growing a nitride semiconductor single crystal wafer such as a nitride GaN wafer by a vapor phase growth method, and a method for manufacturing a GaN wafer therefrom, and in particular, an HVPE for manufacturing a GaN wafer having a reactor for impurity control. It relates to an apparatus and a method of manufacturing GaN wafers thereby.

GaN, a nitride semiconductor material, is a direct transition type semiconductor material with a band gap of 3.4 eV and is attracting attention as a material for light emitting devices such as LEDs and LDs. In addition, GaN has strong physical properties, so its breakdown voltage and electron saturation velocity are very high, and it has a wide bandgap, so it operates with high output in poor environments such as high temperature and radiation. It can be a material used as a high temperature/high power/high speed electronic device. As a method of manufacturing such a GaN single crystal wafer, the HVPE method is the most common method and most of the GaN substrates commercially available are those manufactured by the HVPE method. The HVPE method is one of the chemical vapor deposition methods (CVD method). It is suitable for the growth of GaN thick films or bulk GaN crystals due to the advantages that the growth rate is fast, the raw material is inexpensive, the impurity concentration is relatively low, and excellent crystal quality can be obtained. It is mainly used. In contrast, when methods such as the Na flux method and the Ammono-thermal method are applied, point defects occur in the growth process of the GaN single crystal, and impurities are mixed, so it is difficult to apply for electronic devices. When a GaN wafer is used for an electronic device, it is possible to implement an electronic device capable of high-speed operation with a higher power than that of Si or GaAs. When a GaN wafer is used for such an electronic device, impurities present in the GaN wafer adversely affect the performance of the electronic device, so very precise impurity control is essential.However, the known HVPE method using a quartz tube is 5x10 ¹⁵ An impurity concentration as low as /cm 3 could not be obtained. More specifically, HCl gas and the modified (quartz) is used at a high temperature of about 1,050 ℃ a GaN material is grown to finely reaction and decomposition of SiO2 to SiO + (1/2) O2, and O ₂ is an exploded SiO grown GaN It is mixed in and acts as a cause of increasing the concentration of impurities such as Si and O in the GaN crystal. As a prior art related to the manufacture of GaN wafers, Patent Registration No. 10-1517808 discloses a method of growing GaN on a silicon substrate that maximizes crystallinity of a GaN thin film deposited on a silicon substrate and enables stable growth without cracking. In addition, Patent Registration No. 10-1873568 is a substrate for growing a GaN-based semiconductor layer having a structure that can greatly shorten the processing time of the CLO (Chemical lift-off) process used to separate the GaN-based semiconductor layer from the substrate, and its manufacturing method. Is disclosed. The presented prior art or known art does not disclose a growth apparatus and method for reducing the content of impurities to have uniform properties.

The present invention has the following objects to solve the problems of the prior art.

Prior Art 1: Patent Registration No. 10-1517808 (Electronics Research Institute, 2015.05.06. Announcement) GaN growth method on silicon substrate for crack reduction Prior art 2: Patent registration number 10-1873568 (Korea Photonics Technology Institute, 2018.07.03. Announcement) GaN-based semiconductor layer growth substrate and its manufacturing method

An object of the present invention is to provide an HVPE apparatus for manufacturing a GaN wafer capable of growing a GaN single crystal having a high purity by limiting the incorporation of impurities, and a method for manufacturing a GaN wafer thereby.

According to a preferred embodiment of the present invention, an HVPE apparatus for manufacturing a GaN wafer comprises: a main tube; A reactor chamber for growing a single crystal of GaN nitride semiconductor disposed in the main tube; A first heating furnace installed on the circumferential surface of the main tube to heat the semiconductor material in the source region; And a second heating furnace installed on the circumferential surface of the main tube 11 so as to heat to a higher temperature than the first heating furnace, and the growth region heated by the second heating furnace is a material that limits the generation of Si or O. Is protected by

According to another suitable embodiment of the present invention, the limiting material is pyrolytic boron nitride (PBN) or pyrolytic graphite (PG).

According to another suitable embodiment of the present invention, the limiting material is formed into a diaphragm structure surrounding a susceptor onto which a wafer is loaded.

According to another suitable embodiment of the present invention, the diaphragm structure includes an inlet diaphragm formed with a plurality of inlet holes for supplying gas.

According to another suitable embodiment of the invention, the diaphragm structure comprises at least one nozzle tube for supply of GaCl.

According to still another suitable embodiment of the present invention, a method of growing a substrate by the HVPE method comprises: loading a substrate into a reactor chamber; Setting a reaction restriction area; Heating the source region and the growth region to a predetermined temperature, respectively; Supplying an inert gas to the reactor chamber; Nitriding the substrate by supplying NH3; GaCl is generated and supplied according to the supply of HC1, and thus GaN is grown on the substrate; After the growth is completed, the source region and the growth region are cooled to unload the substrate, and the reaction restriction region is set based on a predetermined heating temperature of the growth region.

The HVPE apparatus for manufacturing a GaN wafer according to the present invention can grow a GaN nitride semiconductor single crystal having a very low impurity concentration such as Si and O as compared to a known HVPE growing apparatus using a quartz material. The manufacturing apparatus according to the present invention can obtain a GaN nitride semiconductor single crystal of uniform quality by significantly reducing the temperature variation inside the reactor by using a material of pyrolytic boron nitride (PBN) or pyrolytic graphite (PG) having high thermal conductivity. In addition, the manufacturing method according to the present invention makes it possible to manufacture a GaN nitride semiconductor substrate for high-temperature/high-power/high-speed electronic devices having a very low impurity concentration and uniform quality.

1 shows an embodiment of an HVPE device for manufacturing a GaN wafer according to the present invention.
2 shows an embodiment of a reactor chamber applied to the HVPE device according to the present invention.
3 shows an embodiment of a method of manufacturing a GaN wafer according to the present invention.

In the following, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the embodiments are for a clear understanding of the present invention, and the present invention is not limited thereto. In the following description, components having the same reference numerals in different drawings have similar functions, so if they are not necessary for the understanding of the invention, they will not be described repeatedly, and well-known components will be briefly described or omitted, but the present invention It should not be understood as being excluded from the embodiment of.

1 shows an embodiment of an HVPE device for manufacturing a GaN wafer according to the present invention.

Referring to FIG. 1, an HVPE apparatus for manufacturing a GaN wafer includes a main tube 11; A reactor chamber 12 for growing a single crystal of GaN nitride semiconductor disposed in the main tube 11; A first heating furnace (14a) installed on the circumferential surface of the main tube (11) to heat the semiconductor raw material in the source region; And a second heating furnace 14b installed on a circumferential surface of the main tube 11 so as to heat to a higher temperature than the first heating furnace 14a, and the growth region heated by the second heating furnace 14b is It is protected by a material that limits the generation of Si or O.

The main tube 11 may be made of quartz or a similar material to form an accommodation space therein. A second flange (16a) for supplying gas is coupled to one part of the main tube (11), and the support (17) for supporting the reactor chamber (12) is fixed to the other part, and the gas is discharged after the reaction. The flange 16b may be coupled. It may be made in a structure that prevents gas from contacting from the outside of the main tube 11, and a reactor chamber 12 for growing GaN on a substrate may be installed inside the main tube 11. GaN nitride semiconductor single crystal growth may be performed in the reactor chamber 12, and supply pipes 151 and 153 for growth may be connected. For example, a first supply pipe 151 for supplying N ₂ , H ₂ and NH ₃ for nitriding a substrate from the outside of the main tube 11 may be connected to the reactor chamber 12. In addition, the Ga boat 13 and the reactor chamber 12 may be connected to allow gas flow by a third supply pipe 153 for supplying GaCl gas for single crystal growth from the Ga boat 13. The second supply pipe 152 is connected to the Ga boat 13 installed inside the main tube 11 so that HCl gas may be supplied from the outside. In addition, GaCl is generated in the Ga boat 13 and supplied to the reactor chamber 12 through the third supply pipe 153 so that GaN may be grown. In the process of injecting the gas source into the reactor chamber 12 and in the process of growing GaN, the growth region needs to be heated to a predetermined temperature. For this, a heating means may be installed around the main tube 11 or at another suitable location. A first heating furnace 14a may be installed around a region surrounding the Ga boat 13. The first heating furnace 14a is installed below the upper flange 16a to heat the periphery of the semiconductor raw material in the source region. H ₂ , N ₂ or a mixed gas thereof and NH ₃ gas for growth corresponding to the carrier gas supplied to the reactor chamber 12 through the first supply pipe 151 by the first heating furnace 14a are heated. I can. In addition, HCl for growth and GaCl gas supplied through the second and third supply pipes 152 and 153 may be heated. The second heating furnace 14b may be installed on the circumferential surface of the main tube 11 for heating the reactor chamber 12, and for example, may be installed below the first heating furnace 14a. The reactor chamber 12 may be, for example, a sapphire, SiC, GaAs, Si or GaN substrate, and in the reactor chamber 12, GaN may be grown on such a substrate. During such a growth process, the inside of the reactor chamber 12 needs to be maintained in a predetermined temperature range, and the reactor chamber 12 may be heated by the second heating furnace 14. The source region corresponding to the upper region of the main tube 11 may be heated by the first heating furnace 14a to be maintained at a temperature of 900° C. or lower, for example. In addition, the second heating furnace 14b may be heated so that the temperature of the inside of the reactor or the growth region is maintained at 1,000 to 1,100°C. The reactor chamber 12 may be supported by the support 17, and the GaN nitride semiconductor single crystal may be grown while being maintained at a predetermined temperature by the second heating furnace 14b. After the growth is completed, gas used in the process may be discharged through the lower flange 16b. In addition, the reactor chamber 12 may be cooled and the substrate may be unloaded.

According to one embodiment of the present invention, the growth region heated by the second heating furnace 14b may be protected with a material that limits the generation of Si or O. The main tube 11 may be formed of quartz or a similar material, and HCl may be supplied as a gas for growth. Crystal and HCl can react at a temperature of, for example, about 1,050 ℃ to decompose the crystal into SiO and (1/2)O ₂ , and thereby SiO or O is incorporated into the GaN crystal during the growth of the GaN nitride single crystal. Can be. As a result, a GaN nitride semiconductor wafer containing impurities such as Si and O may be manufactured, thereby causing a problem that it is difficult to manufacture a GaN wafer for an electronic device. Specifically, when a GaN nitride semiconductor wafer is grown using a crystal material HVPE reaction device, the Si impurity may be 1x10 ¹⁷ /cm 3 or higher, and the O impurity concentration may be 5x10 ¹⁶ /cm 3 or higher. In addition, since the impurity concentration required for the GaN wafer for electronic devices should be 5x10 ¹⁵ /cm 3 or less, it is difficult to manufacture a GaN wafer for electronic devices in the case of a known quartz HVPE reaction device. In order to solve such a problem, a means for limiting the generation of Si or O may be formed in the device of the HPVE according to the present invention, for example, at least the reactor chamber 12 is from a material capable of generating Si or O. Can be protected.

This is described below.

2 shows an embodiment of a reactor chamber applied to the HVPE apparatus according to the present invention.

Referring to FIG. 2, a material that limits the generation of SiO or O is a pyrolytic boron nitride (PBN) or pyrolytic graphite (PG). Using such a material, the wafer W may be formed in a diaphragm structure surrounding the susceptor 21 on which the wafer W is loaded. The diaphragm structure may include an inflow diaphragm 23b having a plurality of inflow holes 24_1 to 24_N for supplying gas. In addition, the diaphragm structure may include at least one nozzle tube 25, 251, 252 for supplying GaCl.

The main tube portion 26 in which the reactor chamber 12 is disposed may be made of a quartz material, and at least a portion of the reactor chamber 12 may be formed of, for example, pyrolytic boron nitride (PBN) or pyrolytic graphite (PG). have. The susceptor 21 may be disposed inside the reactor chamber 12 to have a structure in which GaN can be grown on a substrate such as a wafer W. The reactor chamber 12 may include a sealing diaphragm 23a forming a circumferential wall and an inflow diaphragm 23b in which a plurality of inflow holes 24_1 to 24_N are formed. The sealing diaphragm 23a may have a function of a protective tube protecting the inside of the reactor. In addition, a source gas or a carrier gas may be introduced into the reactor chamber 12 through the inlet diaphragm 23b. The inlet holes 24_ 1 to 24_N formed in the inlet diaphragm 23b may have a diameter of, for example, 2 to 10 mm, and may be formed uniformly on both sides based on the nozzle tubes 25, 251, 252. . The inlet holes 24_1 to 24_N are 1/2 to 4/ of the inlet diaphragm 23b around the nozzle tubes 25, 251, 252 so as to prevent the source gas from flowing back upward of the reactor chamber 12. It can be formed in a region that becomes 5. A gas such as, for example, N ₂ , H _2, or NH ₃ may be introduced into the reactor chamber 12 through the inlet holes 24_1 to 24_N and guided to the wafer W. Nozzle tubes 25, 251, 252 made of, for example, pyrolytic boron nitride (PBN) or pyrolytic graphite (PG) material may be formed at the center of the inflow diaphragm 23b. The nozzle tubes 25, 251, 252 may be of a double structure, for example, and surround the central nozzle tube 25 and the central nozzle tube 25 for induction of GaCl, while the outer periphery of the central nozzle tube 25 It may consist of peripheral nozzle tubes 251 and 252 through which gas such as N ₂ or H ₂ flows along the surface. The center nozzle tube 25 may be connected to the Ga boat described above, and the nozzle tubes 25, 251, 252 may be formed in a structure of various lengths protruding upward of the inlet diaphragm 23b, and mixed with NH3 gas. It has a structure that cannot be done. The susceptor 21 disposed inside the sealing diaphragm 23a to grow the loaded wafer W may be supported by the susceptor support 211.

According to one embodiment of the present invention, the susceptor protection tube 22 may be formed along the circumferential surface of the susceptor 21, and the sesator protection tube 22 is PBN (pyrolytic boron nitride) or PG ( pyrolytic graphite) material. The susceptor protection tube 22 may be formed in a structure extending downward from the upper surface of the susceptor 21, and an inner diameter capable of forming a separation gap allowing gas flow from the circumferential surface of the susceptor 21 Can have The susceptor support 211 may have a rotatable structure, and a gas such as N ₂ or H ₂ may flow along the circumferential surface of the susceptor support 211. In addition, N ₂ or H ₂ may flow along the space formed by the susceptor protection tube 22 and the sealing partition wall 23a. Generation of Si or O is limited by protecting the growth region inside the reactor chamber 12 by a material such as pyrolytic boron nitride (PBN) or pyrolytic graphite (PG). Accordingly, impurities such as Si or O may be prevented from being mixed in the process of growing GaN.

Hereinafter, a process of growing GaN by a reactor chamber having such a structure will be described.

3 shows an embodiment of a method of manufacturing a GaN wafer according to the present invention.

Referring to FIG. 3, the method of growing a substrate by the HVPE method includes loading a substrate into a reactor chamber (P31); Step P32 of setting a reaction restriction region; Heating the source region and the growth region to a predetermined temperature, respectively (P33); Supplying an inert gas to the reactor chamber (P34); Nitriding the substrate by supplying NH3 (P35; GaCl is generated and supplied by the supply of HCl, and GaN is thus grown on the substrate (P36)); After growth is completed, the source region and the growth region are Cooling and unloading the substrate (P37, P38), and the reaction restriction region is set based on a predetermined heating temperature of the growth region.

A substrate such as, for example, a sapphire substrate may be loaded onto the susceptor inside the reactor chamber, and at least one substrate may be loaded onto the susceptor (P31). The reaction restriction region may be set in advance in the reactor chamber or around the susceptor, and the reaction restriction region may be set based on, for example, a heated temperature (P32). As described above, the reaction restriction region may be a region in which impurities such as Si or O may be generated by a reaction between a source gas or a carrier gas and a material forming the reactor chamber. A protective diaphragm for limiting the reaction may be formed in the reaction restricted region, and the protective diaphragm may be formed of, for example, a material such as pyrolytic boron nitride (PBN) or pyrolytic graphite (PG). It can be a PBN or a compound with the following characteristics.

PBN

Chemical formula: BN, molecular weight: 24.82 g·mol ¹ , appearance: colorless crystals, density: 2.1 (h-BN); 3.45 (c-BN) g/cm ³ , Melting point: 2,973 °C (5,383 °F; 3,246 K) sublimates (cBN), Electron mobility: 200 cm ² /(V·s) (cBN), Refractive index: 1.8 (h-BN); 2.1 (c-BN)

PG

Chemical Formula: C, Density: 1.30 to 2.265 g/cm 3, Appearance: Black solid in sheet shape, solubility in water: N/A, melting point: N/A, electrical resistance: 0.15-0.25 Ω·cm to 0.45 μΩ Cm, tensile strength: 200 MPa, thermal expansion coefficient: 20 μm/m°C

When the protective diaphragm is formed by such a pyrolytic boron nitride (PBN) or pyrolytic graphite (PG) material, or the entire reactor chamber is formed, HCl or NH as the source gas at the growth temperature of the GaN nitride semiconductor crystal is in the range of 1,000°C to 1,100°C. ₃ does not react and impurities contaminating the reactor may not be generated. When the reaction restriction region is set in advance (P32), the source region and the growth region may be heated to a predetermined temperature (P33). The apparatus for the application of the HVPE method can be divided into two areas, for example, the Ga metal source heated by the first heating furnace is in the Ga boat area and the second heating furnace where HCl gas reacts to generate GaCl gas. It may be divided into a GaN single crystal growth region on which a substrate heated by the heating is mounted. The Ga boat region may be heated to a temperature of 900° C. or less or 800 to 900° C., for example. In addition, GaCl gas and NH3 gas corresponding to the source gas may be supplied to the GaN single crystal growth region over the substrate, and nitrogen, hydrogen, or a mixed gas of nitrogen and hydrogen may be supplied as an atmospheric gas. In addition, a doping gas for manufacturing an n-type semiconductor may be supplied. Such a growth region may be heated to 1000 ℃ to 1100 ℃. When quartz is used as the reactor material, impurities such as Si and O are generated, so PBN (pyrolytic boron nitride) or PG (pyrolytic graphite) was used as a material constituting the reactor chamber in the second heating furnace region. That is, the main tube that connects the upper flange and the lower flange, which is a part constituting the outside of the entire reactor, is made of quartz material, and the inner material of the first heating furnace area is also composed of modified material. As shown in FIG. 2, the internal materials were all made of PBN (pyrolytic boron nitride) or PG (pyrolytic graphite) material. An inert gas such as N ₂ may be supplied to the reactor chamber to be made without oxygen (P34), and then a gas such as NH3 may be supplied to the wafer W to be nitrided (P35). . When the nitriding treatment is completed, HCl is supplied to Ga, which is a semiconductor raw material, so that CaCl can be generated, and thus, nitride semiconductor single crystal GaN can be grown on the substrate (P36). During the growth process, the growth rate of the nitride semiconductor single crystal GaN may be 20 to 200 μm/hr, and the thickness of the GaN thick film grown on the substrate may be, for example, about 500 μm. When such growth is performed, the first and second heating furnaces may be cooled to a room temperature range (P37), and when cooling is completed, the growth-completed substrate may be unloaded (P38). By setting the reaction restriction region and forming a protective structure in the form of a partition wall with a material that restricts the reaction, impurities such as Si or O may be prevented from being mixed in the growth process. In addition, the GaN substrate manufactured in this way has a very low impurity concentration and may have uniform characteristics. Accordingly, for example, a GaN nitride semiconductor substrate suitable for high temperature/high power/high speed electronic devices may be manufactured.

The present invention has been described in detail above with reference to the presented embodiments, but those of ordinary skill in this field will be able to make various modifications and modifications without departing from the technical spirit of the present invention with reference to the presented embodiments. . The present invention is not limited by such modifications and variations of the invention, but is limited by the claims appended below.

11: main tube 12: reactor chamber
13: Ga boat 14a, 14b: heating furnace
151, 152, 153: supply pipe: 16a, 16: flange
17: support
21: susceptor 22: susceptor protective tube
23a, 23b: diaphragm 24_1 to 24_N: inlet hole
25, 251, 252: nozzle tube

Claims (6)

Main tube 11;
A reactor chamber 12 for growing a single crystal of GaN nitride semiconductor disposed in the main tube 11;
A first heating furnace (14a) installed on the circumferential surface of the main tube (11) to heat the semiconductor raw material in the source region; And
It includes a second heating furnace (14b) installed on the circumferential surface of the main tube 11 to heat to a higher temperature than the first heating furnace (14a),
The HVPE apparatus for manufacturing a GaN wafer, characterized in that the growth region heated by the second heating furnace 14b is protected with a material that limits the generation of Si or O. The HVPE apparatus for manufacturing a GaN wafer according to claim 1, wherein the limiting material is a pyrolytic boron nitride (PBN) or a pyrolytic graphite (PG). The HVPE apparatus for manufacturing a GaN wafer according to claim 1, wherein the limiting material is formed in a diaphragm structure surrounding the susceptor (21) into which the wafer (W) is loaded. The HVPE apparatus for manufacturing a GaN wafer according to claim 3, wherein the diaphragm structure includes an inflow diaphragm (23b) formed with a plurality of inflow holes (24_1 to 24_N) for supplying gas. The HVPE apparatus according to claim 3, wherein the diaphragm structure comprises at least one nozzle tube (25, 251, 252) for supplying GaCl. In the method of growing a substrate by the HVPE method,
Loading a substrate into the reactor chamber;
Setting a reaction restriction area;
Heating the source region and the growth region to a predetermined temperature, respectively;
Supplying an inert gas to the reactor chamber;
Nitriding the substrate by supplying NH3;
GaCl is generated and supplied according to the supply of HC1, and thus GaN is grown on the substrate;
After the growth is completed, the source region and the growth region are cooled to unload the substrate,
A method of growing a substrate by the HVPE method, wherein the reaction restriction region is set based on a predetermined heating temperature of the growth region.

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