Method and apparatus for growing III-V compound single crystals by hydride vapor phase epitaxy

Abstract

The present invention discloses a method and apparatus for growing a III-V compound single crystal by hydride vapor phase epitaxy. The method comprises: introducing a III element source, a nitrogen source, and a carrier gas into a HVPE reaction chamber, and sequentially passing through a first region, a second region, and a third region of the reaction chamber, adjusting the first region, the second region, and the third region of the reaction chamber to a first temperature, a second temperature, and a third temperature, respectively, causing the III element source and the nitrogen source to react in the first region to form a III nitride single crystal, causing the III element source and hydrogen to react in the second region to form a III element element, and causing the nitrogen source and a halogen hydride to react in the third region to form an ammonium salt. An embodiment of the present invention provides a method for growing a III nitride single crystal by hydride vapor phase epitaxy, which improves the yield and purity of the III nitride single crystal, can recover the III element element element, and reduces the preparation cost of the III nitride single crystal.

Description

Technical Field

[0001] The present invention relates to a hydride vapor phase epitaxy device, in particular to a method and device for growing III-V compound single crystals using a hydride vapor phase epitaxy method, belonging to the technical field of semiconductor epitaxial devices. Background Art

[0002] The third generation of semiconductor materials is a wide bandgap semiconductor material represented by III-V compounds (such as gallium nitride GaN), silicon carbide (SiC), diamond, and zinc oxide. Its bandgap energy can reach 3.3 to 5.5 eV. Compared with traditional first-generation semiconductor materials such as silicon (Si) and germanium (Ge), and second-generation semiconductor materials such as gallium arsenide (GaAs) and indium phosphide (InP), third-generation semiconductor materials have unique properties such as large bandgap width, high breakdown electric field, large thermal conductivity, high electron saturation drift velocity, and small dielectric constant. These properties make them show great application potential in optoelectronic devices, power electronics, radio frequency microwave devices, lasers, and detectors, and are a hot topic of research in the semiconductor field in countries around the world.

[0003] Methods for growing III-V compound single crystals (such as GaN single crystals) include hydride vapor phase epitaxy (HVPE), high-pressure nitrogen solution methods, ammonothermal methods, and sodium flux methods. However, single crystal growth technology is currently immature and has yet to achieve widespread application. Among these methods, the ammonothermal method easily produces larger single crystals and has the potential for mass production of III-V compound single crystals.

[0004] Taking the hydride vapor phase epitaxy method for gallium nitride growth as an example, the reaction principle is: ①Ga+HCl→GaCl+H2, ②GaCl+NH3→GaN (single crystal)+HCl+H2, and a large number of by-products will be produced during the HVPE growth process: ③GaCl+NH3→GaN (polycrystalline)+HCl+H2, ④2GaCl+H2→Ga+2HCl, ⑤NH3+HCl→NH4Cl.

[0005] Figure 1The structure of a conventional HVPE growth system and a schematic diagram of byproduct deposition within the reaction chamber during gallium nitride single crystal growth are shown. In existing HVPE growth systems, in addition to depositing gallium nitride on the substrate, the reaction chamber also contains many other parasitic products, such as polycrystalline gallium nitride, metallic gallium, and ammonium chloride. The primary material of the HVPE growth system's reaction chamber is quartz. Polycrystalline GaN deposited on quartz can clog the quartz pipes, impacting growth. Excessive deposition can also cause the quartz to crack, shortening the system's operating time. Frequent replacement of quartz components can also degrade production stability. Ammonium chloride is the primary deposit within the HVPE exhaust system. In conventional HVPE, ammonium chloride deposits within the reaction chamber and the exhaust system, making it difficult to clean due to multiple locations. Ammonium chloride deposited within the reaction chamber can also cause particle contamination within the reaction chamber, impacting growth.

[0006] Therefore, in existing HVPE growth systems, multiple parasites will mix in the reaction chamber, causing changes in the atmosphere in the reaction chamber, thereby affecting the effective reaction time of the reaction chamber and the cleanliness of the reaction chamber; and the mixing of multiple different substances will also lead to problems such as difficult waste disposal and low reaction source utilization. Summary of the Invention

[0007] The main purpose of the present invention is to provide a method and apparatus for growing III-V compound single crystals by hydride vapor phase epitaxy, so as to overcome the deficiencies in the prior art.

[0008] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0009] An embodiment of the present invention provides a method for growing a III-V compound single crystal by hydride vapor phase epitaxy, comprising: introducing a first source material and a second source material into a reaction chamber, wherein the first source material comprises a Group III element, and the second source material comprises a Group V element; setting a first region, a second region, and a third region in the reaction chamber to different temperatures, respectively, so that the first source material and the second source material react in the first region of the reaction chamber to generate a III-V compound single crystal and a first by-product; and causing at least a portion of the first by-product to react with unreacted first source material in the second region to generate a recyclable Group III element single substance and a second by-product; and causing at least a portion of the first by-product and / or at least a portion of the second by-product to react with unreacted second source material in the third region to generate a recyclable product.

[0010] An embodiment of the present invention further provides a method for growing a group III nitride single crystal by hydride vapor phase epitaxy, which comprises:

[0011] A group III element source, a nitrogen source, and a carrier gas are introduced into an HVPE reaction chamber and sequentially pass through a first region, a second region, and a third region within the reaction chamber, wherein the first region includes a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, a substrate is distributed within the group III nitride single crystal growth region, the group III element source includes a group III element halide, and the nitrogen source includes NH3;

[0012] Setting the temperature of the group III nitride single crystal growth region to a first temperature so that a group III element source and a nitrogen source undergo a first reaction in the group III nitride single crystal growth region to generate a group III nitride single crystal, hydrogen, and a halogen hydride, and depositing the group III nitride single crystal on a substrate, and setting the temperature of the peripheral region to a second temperature, wherein the first temperature is a temperature suitable for growing the group III nitride single crystal and the second temperature is greater than the first temperature;

[0013] Setting the temperature of the second region to a third temperature so that at least the hydrogen generated by the first reaction reacts with the source of the group III element in the second region to generate a simple substance of the group III element and a halogen hydride, wherein the third temperature is higher than a formation temperature of the ammonium salt and lower than a cracking temperature of the halide of the group III element;

[0014] The temperature of the third region is set to a fourth temperature so that at least the halogen hydride generated by the first reaction and / or the second reaction reacts with the nitrogen source in the third region to generate ammonium salt. The fourth temperature is not higher than the decomposition temperature of the ammonium salt.

[0015] An embodiment of the present invention further provides an apparatus for growing a group III nitride single crystal by hydride vapor phase epitaxy, comprising:

[0016] An HVPE reaction chamber, the HVPE reaction chamber comprising a first region, a second region, and a third region sequentially connected along a preset direction, the first region comprising a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, a substrate being distributed within the group III nitride single crystal growth region, the group III nitride single crystal growth region being configured to allow at least a group III element source and a nitrogen source to react to generate a group III nitride single crystal, hydrogen, and a halogen hydride, and to deposit the group III nitride single crystal on the substrate; a group III element single substance collection mechanism being disposed within the second region and configured to allow the group III element source and hydrogen to react to generate a group III element single substance and a halogen hydride; and the third region being configured to allow a nitrogen source and a halogen hydride to react to generate an ammonium salt;

[0017] a heating device, which is used at least to respectively make the temperatures of the III-nitride single crystal growth region, the peripheral region, the second region, and the third region reach a first temperature, a second temperature, a third temperature, and a fourth temperature;

[0018] The nitrogen source and group III element source supply mechanism is connected to the HVPE reaction chamber and is at least used to input the nitrogen source and group III element source for growing group III nitride single crystal into the HVPE reaction chamber.

[0019] Compared with the prior art, the advantages of the present invention include:

[0020] 1) The embodiment of the present invention provides a hydride vapor phase epitaxy apparatus for growing group III nitride single crystals. The apparatus has a simple structure and requires only simple modification of the reaction chamber to reduce the deposition of reaction byproducts and enable classified recovery of reaction byproducts.

[0021] 2) The present invention provides a method for growing group III nitride single crystals using a group III nitride hydride vapor phase epitaxy method, which improves the yield and purity of group III nitride single crystals. Furthermore, the present invention reduces the formation of group III nitride polycrystals through precise control of multiple regions (temperature and length), dilution gas assistance, and localized heating. Furthermore, the present invention achieves high-purity centralized recovery of group III elements and byproducts such as ammonium salts, reducing the cost of group III element recovery and the frequency of equipment maintenance.

[0022] 3) An embodiment of the present invention provides a hydride vapor phase epitaxy apparatus for growing group III nitride single crystals. By adjusting the temperature in different chambers, a temperature gradient is formed in different areas of the reaction chamber, and airflow dilution is increased, thereby decomposing excess ammonium salts and increasing the yield of group III elements.

[0023] 4) An embodiment of the present invention provides a hydride vapor phase epitaxy device for growing group III nitride single crystals, which makes the temperature of the recovery area (the recovery area includes the second area and the third area) in the reaction chamber lower than the cracking temperature of the halide of the group III element and higher than the temperature for forming the ammonium salt, thereby promoting the decomposition of excess halide of the group III element. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 The structure of the HVPE growth system in the prior art and a schematic diagram of by-product deposition in the reaction chamber during gallium nitride single crystal growth;

[0026] Figure 2 It is a schematic diagram of the structure of a reaction chamber in a hydride vapor phase epitaxy device for growing gallium nitride single crystals provided in a typical embodiment of the present invention, and a schematic diagram of the deposition of by-products in the reaction chamber when growing gallium nitride single crystals. DETAILED DESCRIPTION

[0027] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The following will further explain this technical solution, its implementation process and principles.

[0028] The reaction principle of gallium nitride growth by hydride vapor phase epitaxy is: ①Ga+HCl→GaCl+H2, ②GaCl+NH3→GaN (single crystal)+HCl+H2, and a large number of by-products are produced during the HVPE growth process: ③GaCl+NH3→GaN (polycrystalline)+HCl+H2, ④2GaCl+H2→Ga+2HCl, ⑤NH3+HCl→NH4Cl. Reaction ② is the primary reaction and the goal of the HVPE system, which is to produce as many GaN single crystals as possible. However, in conventional HVPE reaction systems, the proportion of GaCl in reaction ② that forms single-crystalline GaN is only 5-30%. Most of the GaCl is ultimately converted into reaction byproducts and exists in various forms, such as GaN polycrystals, Ga, Ga*NH4Cl, and GaCl*NH4Cl. This results in low Ga utilization and increases the cost of growing GaN single crystals. Among these byproducts, metallic Ga has the highest purity and the lowest purification difficulty. If it can be converted into metallic Ga as much as possible, the purification cost can be reduced, thereby lowering the overall cost of preparing GaN single crystals.

[0029] An embodiment of the present invention provides a method for growing a III-V compound single crystal by hydride vapor phase epitaxy, comprising: introducing a first source material and a second source material into a reaction chamber, wherein the first source material comprises a Group III element, and the second source material comprises a Group V element; setting a first region, a second region, and a third region in the reaction chamber to different temperatures, respectively, so that the first source material and the second source material react in the first region of the reaction chamber to generate a III-V compound single crystal and a first by-product; and causing at least a portion of the first by-product to react with unreacted first source material in the second region to generate a recyclable Group III element single substance and a second by-product; and causing at least a portion of the first by-product and / or at least a portion of the second by-product to react with unreacted second source material in the third region to generate a recyclable product.

[0030] Furthermore, the first region includes a III-V compound single crystal growth region and a peripheral region radially surrounding the III-V compound single crystal growth region, the III-V compound single crystal growth region is set to a temperature suitable for generating a III-V compound single crystal, and the temperature of the peripheral region is higher than the temperature of the III-V compound single crystal growth region.

[0031] Furthermore, the method further includes: inputting a dilution gas into the peripheral region to reduce the concentration of the first source material and the second source material in the peripheral region, thereby preventing the first source material and the second source material from reacting in the peripheral region to generate III-V compound polycrystals.

[0032] Furthermore, at least a portion of the dilution gas can react with the unreacted first source material in the second region to generate the Group III element.

[0033] Furthermore, at least a portion of the dilution gas can react with the unreacted second source material in the third region to generate the recoverable product.

[0034] Furthermore, the temperature of the second zone is set to be higher than the formation temperature of the recyclable product and lower than the decomposition temperature of the first source material, and the temperature of the third zone is set to be no higher than the decomposition temperature of the recyclable product.

[0035] Furthermore, the method further includes: setting an operating area between the second area and the third area for inserting or removing a growth substrate of a III-V compound single crystal into or from the first area, and setting the temperature of the operating area to be higher than the generation temperature of the recyclable product.

[0036] An embodiment of the present invention further provides a method for growing a group III nitride single crystal by hydride vapor phase epitaxy, which comprises:

[0037] A group III element source, a nitrogen source, and a carrier gas are introduced into an HVPE reaction chamber and sequentially pass through a first region, a second region, and a third region within the reaction chamber, wherein the first region includes a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, a substrate is distributed within the group III nitride single crystal growth region, the group III element source includes a group III element halide, and the nitrogen source includes NH3;

[0038] Setting the temperature of the group III nitride single crystal growth region to a first temperature so that a group III element source and a nitrogen source undergo a first reaction in the group III nitride single crystal growth region to generate a group III nitride single crystal, hydrogen, and a halogen hydride, and depositing the group III nitride single crystal on a substrate, and setting the temperature of the peripheral region to a second temperature, wherein the first temperature is a temperature suitable for growing the group III nitride single crystal and the second temperature is greater than the first temperature;

[0039] Setting the temperature of the second region to a third temperature so that at least the hydrogen generated by the first reaction reacts with the source of the group III element in the second region to generate a simple substance of the group III element and a halogen hydride, wherein the third temperature is higher than a formation temperature of the ammonium salt and lower than a cracking temperature of the halide of the group III element;

[0040] The temperature of the third region is set to a fourth temperature so that at least the halogen hydride generated by the first reaction and / or the second reaction reacts with the nitrogen source in the third region to generate ammonium salt. The fourth temperature is not higher than the decomposition temperature of the ammonium salt.

[0041] Furthermore, the peripheral area is an area near the tube wall of the HVPE reaction chamber.

[0042] Furthermore, the method specifically includes: adjusting the heating power of the HVPE reaction equipment for the peripheral zone so that the temperature of the peripheral zone reaches the second temperature; or providing an auxiliary heating device in the peripheral zone so that the temperature of the peripheral zone reaches the second temperature.

[0043] Furthermore, the method further comprises: inputting a dilution gas into the peripheral area to reduce the concentration of the Group III element source and the nitrogen source in the peripheral area.

[0044] Furthermore, the dilution gas contains hydrogen, and the hydrogen derived from the dilution gas also participates in the second reaction.

[0045] Furthermore, the input flow rate of the hydrogen is 0.5-50 slm.

[0046] Furthermore, the dilution gas contains halogen hydride, and the halogen hydride derived from the dilution gas also participates in the third reaction.

[0047] Furthermore, the input flow rate of the halogen hydride is less than the generation rate of the halogen hydride in the first reaction.

[0048] Furthermore, the input flow rate of the halogen hydride is 0.05-1slm.

[0049] Furthermore, the method includes: maintaining the hydrogen concentration in the HVPE reaction chamber at 20%-80% and the halogen hydride concentration at 1%-10%.

[0050] Furthermore, the nitrogen source input into the HVPE reaction chamber is in excess.

[0051] Furthermore, the HVPE reaction chamber further includes operating zones distributed between the second area and the third area, and the temperature of the operating zones is set to be higher than the formation temperature of the ammonium salt.

[0052] Furthermore, the method further includes: providing a Group III element simple substance collecting mechanism in the second region.

[0053] Furthermore, the group III element simple substance collecting mechanism includes a group III element simple substance collecting plate.

[0054] Furthermore, the Group III element source includes GaM x 、InM x 、AlM x or BM x , x ranges from 1 to 3, and M includes Cl, Br or I.

[0055] An embodiment of the present invention further provides an apparatus for growing a group III nitride single crystal by hydride vapor phase epitaxy, comprising:

[0056] An HVPE reaction chamber, the HVPE reaction chamber comprising a first region, a second region, and a third region sequentially connected along a preset direction, the first region comprising a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, a substrate being distributed within the group III nitride single crystal growth region, the group III nitride single crystal growth region being configured to allow at least a group III element source and a nitrogen source to react to generate a group III nitride single crystal, hydrogen, and a halogen hydride, and to deposit the group III nitride single crystal on the substrate; a group III element single substance collection mechanism being disposed within the second region and configured to allow the group III element source and hydrogen to react to generate a group III element single substance and a halogen hydride; and the third region being configured to allow a nitrogen source and a halogen hydride to react to generate an ammonium salt;

[0057] a heating device, which is used at least to respectively make the temperatures of the III-nitride single crystal growth region, the peripheral region, the second region, and the third region reach a first temperature, a second temperature, a third temperature, and a fourth temperature;

[0058] The nitrogen source and group III element source supply mechanism is connected to the HVPE reaction chamber and is at least used to input the nitrogen source and group III element source for growing group III nitride single crystal into the HVPE reaction chamber.

[0059] Furthermore, the apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy also includes:

[0060] a dilution gas supply mechanism connected to the HVPE reaction chamber and configured to supply dilution gas to the peripheral region to reduce the concentrations of the Group III element source and the nitrogen source in the peripheral region, wherein the peripheral region is an area near a tube wall of the HVPE reaction chamber;

[0061] And / or, a group III element simple substance collecting mechanism is provided in the second region.

[0062] Furthermore, the group III element simple substance collecting mechanism includes a group III element simple substance collecting plate.

[0063] Furthermore, the HVPE reaction chamber further includes operating areas distributed in the second area and the third area. The operating areas are provided with operating ports, and the operating ports are provided with operating covers that can be opened and closed.

[0064] Furthermore, the ratio of the lengths of the first region, the second region and the third region is 1:2:2-1:10:4.

[0065] Furthermore, the equipment also includes an exhaust gas treatment mechanism, which is connected to the exhaust gas outlet of the HVPE reaction chamber.

[0066] The technical solution, its implementation process and principles will be further explained below with reference to the accompanying drawings. Unless otherwise specified, the gallium nitride growth source supply mechanism, dilution gas supply mechanism, exhaust gas treatment mechanism, etc. in the hydride vapor phase epitaxy equipment for gallium nitride single crystal growth in the embodiment of the present invention can adopt those known to those skilled in the art and are not specifically limited here.

[0067] See also Figure 2 , a device for growing gallium nitride single crystals by hydride vapor phase epitaxy, comprising:

[0068] An HVPE reaction chamber, the HVPE reaction chamber comprising a first region, a second region, an operating region, and a third region sequentially connected along a preset direction, wherein the first region includes a gallium nitride single crystal growth region and a peripheral region radially surrounding the gallium nitride single crystal growth region, a substrate being distributed within the gallium nitride single crystal growth region, the gallium nitride single crystal growth region being capable of allowing a gallium source and a nitrogen source to react to generate a gallium nitride single crystal, hydrogen, and hydrogen chloride, and depositing the gallium nitride single crystal on the substrate; a metal gallium collection mechanism being disposed within the second region and capable of allowing a gallium source and hydrogen to react to generate metal gallium and hydrogen chloride; and the third region being capable of allowing a nitrogen source and hydrogen chloride to react to generate ammonium chloride.

[0069] a heating device, which is used at least to respectively adjust the temperatures of the gallium nitride single crystal growth region, the peripheral region, the second region, and the third region to a first temperature, a second temperature, a third temperature, and a fourth temperature;

[0070] a nitrogen source and gallium source supply mechanism connected to the HVPE reaction chamber and at least used to input a nitrogen source and a gallium source for growing a gallium nitride single crystal into the HVPE reaction chamber;

[0071] a dilution gas supply mechanism connected to the HVPE reaction chamber and configured to supply dilution gas to the peripheral region to reduce the concentrations of the gallium source and the nitrogen source in the peripheral region, wherein the peripheral region is an area near a tube wall of the HVPE reaction chamber;

[0072] An exhaust gas treatment mechanism is connected to the exhaust gas outlet of the HVPE reaction chamber.

[0073] Specifically, a metal gallium collecting mechanism is provided in the second area. For example, the metal gallium collecting mechanism includes a metal gallium collecting plate. The operating area is provided with an operating port, and an openable and closable operating cover is provided at the operating port.

[0074] Specifically, the ratio of the lengths of the first region, the second region, and the third region is 1:2:2-1:10:4.

[0075] Example 1

[0076] A method for growing a gallium nitride single crystal by hydride vapor phase epitaxy, comprising:

[0077] Provide Figure 2 The apparatus for growing gallium nitride single crystals using hydride vapor phase epitaxy is shown, wherein the gallium nitride single crystal growth region, the peripheral region, the second region, and the third region of the reaction chamber are adjusted to a first temperature, a second temperature, a third temperature, and a third temperature, respectively;

[0078] A gallium source, a nitrogen source, and a carrier gas are introduced into an HVPE reaction chamber and sequentially pass through a first region, a second region, and a third region within the reaction chamber, wherein the first region includes a gallium nitride single crystal growth region and a peripheral region radially surrounding the gallium nitride single crystal growth region, a substrate is distributed within the gallium nitride single crystal growth region, the gallium source includes GaCl, and the nitrogen source includes NH3;

[0079] Setting the temperature of the gallium nitride single crystal growth region to a first temperature so that a gallium source and a nitrogen source undergo a first reaction in the gallium nitride single crystal growth region to generate a gallium nitride single crystal, hydrogen gas, and hydrogen chloride, and depositing the gallium nitride single crystal on a substrate; and setting the temperature of the peripheral region to a second temperature, wherein the first temperature is a temperature suitable for growing the gallium nitride single crystal and the second temperature is greater than the first temperature;

[0080] Setting the temperature of the second region to a third temperature so that at least the hydrogen generated by the first reaction reacts with the gallium source in the second region to produce metallic gallium and hydrogen chloride, wherein the third temperature is higher than the formation temperature of ammonium chloride and lower than the decomposition temperature of gallium chloride;

[0081] Setting the temperature of the third region to a fourth temperature so that at least the hydrogen chloride generated by the first reaction and / or the second reaction reacts with the nitrogen source in the third region to produce ammonium chloride, wherein the fourth temperature is not higher than the decomposition temperature of ammonium chloride; and

[0082] A dilution gas is introduced into the reaction chamber to purge the first region, and a portion of the gallium source, the nitrogen source, and a portion of the H2 and HCl generated by the reaction are purged into the second region and the third region; wherein the first reaction, the second reaction, and the third reaction are respectively represented by Formula 1), Formula 2, and Formula 3;

[0083] GaCl+NH3→GaN+HCl+H2 1)

[0084] GaCl+H2→Ga+HCl 2)

[0085] NH3+HCl→NH4Cl 3).

[0086] Specifically, the first temperature is 1000-1090°C, the second temperature is above 1090°C, the third temperature is 350-800°C, the temperature of the operating zone is 25-350°C, and the fourth temperature is ≥350°C.

[0087] Specifically, the method includes: inputting a dilution gas into the peripheral area of ​​the reaction chamber along the inner wall of the reaction chamber to adjust the H2 concentration in the HVPE reaction chamber to 20%-80% and the HCl concentration to 1%-10%, wherein the dilution gas includes any one of N2, H2 and HCl or a combination of two or more, the input flow rate of any one of N2 and H2 is 0.5-50 slm, and the input flow rate of HCl is less than the generation rate of HCl in the first reaction, for example, the input flow rate of HCl is 0.05-0.1 sccm.

[0088] Specifically, the reaction that forms gallium nitride polycrystals in the gallium nitride single crystal growth region is: GaCl+NH3→GaN (polycrystal)+HCl+H2. The inventors of this case have discovered that when the temperature rises, the forward reaction is inhibited and the reverse reaction is promoted, thereby reducing the efficiency of GaN synthesis. Therefore, increasing the temperature can inhibit the formation of polycrystalline GaN (the formation temperature of single crystals and polycrystals is the same, but the formation state is different on different substrates, single crystals on substrates and polycrystals on quartz); and when the concentration of HCl and H2 in the reaction chamber is higher than 30%, the reverse reaction is promoted, resulting in less polycrystalline GaN synthesis; therefore, when the total flow rate in the reaction chamber is greater than 20slm, when the relative concentration of the source gas is reduced to 20%, the efficiency of the reaction to form gallium nitride polycrystals will also be reduced.

[0089] The inventors of this case also discovered that gallium nitride polycrystals tend to deposit on the walls of the reaction chamber. Therefore, introducing a dilution gas into the reaction chamber along the inner wall of the reaction chamber can effectively prevent gallium nitride polycrystals from depositing on the walls of the reaction chamber. In addition, the present invention also locally heats the peripheral area of ​​the HVPE reaction chamber to increase the temperature of the peripheral area to above 1090°C, thereby inhibiting the reaction, formation, and deposition of gallium nitride polycrystals.

[0090] The implementation principle of a method for growing gallium nitride single crystals by hydride vapor phase epitaxy provided in an embodiment of the present invention at least includes:

[0091] ①Ga+HCl→GaCl+H2, ②GaCl+NH3→GaN (single crystal)+HCl+H2, and a large number of by-products will be produced during the HVPE growth process: ③GaCl+NH3→GaN (polycrystalline)+HCl+H2, ④2GaCl+H2→Ga+2HCl, ⑤NH3+HCl→NH4Cl;

[0092] The gallium source GaCl, the nitrogen source NH3, and the doping source gas are introduced into the HVPE reaction chamber via a carrier gas, so that the gallium source and the nitrogen source react in the gallium nitride single crystal growth region in the form of GaCl+NH3→GaN+HCl+H2 to form a gallium nitride single crystal. Since the temperature in the gallium nitride single crystal growth region is suitable for gallium nitride single crystal growth but not for gallium nitride polycrystal growth, the formation of gallium nitride polycrystals can be reduced. In addition, a dilution gas is introduced into the reaction chamber along the inner wall of the reaction chamber to purge part of the gallium source, the nitrogen source, and part of the H2 and HCl generated by the reaction into the second region and the third region. Since the hydrogen gas used as the dilution gas does not participate in the reaction in the first region, the part of the hydrogen gas is purged into the second region and reacts in the second region in the form of GaCl+H2→Ga+HCl to form metallic gallium. The third temperature is the formation temperature of metallic gallium, and the third temperature is higher than the formation temperature of ammonium chloride but lower than the decomposition temperature of gallium chloride. The increase in the hydrogen flow rate in the second region promotes the production efficiency of metallic gallium.

[0093] Since the fourth temperature of the third region is lower than the temperature of the second region and the gallium nitride single crystal growth region, and this fourth temperature is a temperature at which the reaction NH3+HCl→NH4Cl can occur, the reaction of forming ammonium chloride almost does not occur in the first and second regions. Moreover, since the input NH3 is in great excess and NH3 only participates in the formation reaction of GaN and does not participate in other reactions, the excess ammonia will flow into the third region. In addition, HCl is a product of the reaction to form GaN; excess HCl is also introduced when reducing the production of polycrystalline GaN; and the side reaction ④ will also produce HCl when producing gallium. This part of HCl does not participate in other reactions and will also flow into the third region.

[0094] Specifically, provide Figure 1 、 Figure 2 The apparatus for growing gallium nitride single crystals by hydride vapor phase epitaxy is shown, and the epitaxial growth of gallium nitride single crystals is performed using the hydride vapor phase epitaxy apparatus and corresponding processes;

[0095] After calculation: Figure 1 When preparing gallium nitride single crystals using the equipment and existing process shown (see the background technology section), for every 1000g of metallic gallium consumed, 62.5g of gallium nitride single crystals, 960.8g of gallium nitride polycrystals, 30g of metallic gallium, and 956.1g of a mixture of ammonium chloride and gallium chloride are produced. Measurements show that the gallium content of the mixture of ammonium chloride and gallium chloride is 12%. Furthermore, a large amount of ammonium chloride is deposited on the cavity wall in the wafer loading and unloading area. The surface of the prepared gallium nitride single crystal has a macroscopic defect density of 2 particles / cm2 due to particles such as chamber byproducts. 2 , the reaction chamber needs to be cleaned every time growth is performed.

[0096] by Figure 2 When preparing gallium nitride single crystals using the apparatus and method provided by the present invention, for every 1000g of metallic gallium consumed, 77.2g of gallium nitride single crystals, 360.3g of gallium nitride polycrystals, 550g of metallic gallium, and 1127.8g of a mixture of ammonium chloride and gallium chloride are produced. The gallium content of the mixture of ammonium chloride and gallium chloride is measured to be 6%. Furthermore, the method provided by the present invention results in almost no ammonium chloride deposition on the cavity wall in the wafer loading and unloading area, and the macroscopic defect density on the surface of the prepared gallium nitride single crystal due to particles such as cavity byproducts is 0.3 particles / cm 2 , the reaction chamber only needs to be cleaned every 5 growths.

[0097] By comparison, the present embodiment provides a method for growing gallium nitride single crystals by hydride vapor phase epitaxy, which can convert the proportion of metallic gallium into gallium nitride single crystals from 5.2% (using Figure 1 The equipment and existing process shown in the figure) was increased to 6.4%, the proportion converted to polycrystalline gallium nitride was reduced from 80% to 30%, the proportion converted to metallic gallium was increased from 3% to 55%, the gallium content in ammonium chloride was reduced from 12% to 6%, the cleanliness of the wafer loading and unloading operation area was greatly improved, the macro defect density caused by particle contamination was reduced by an order of magnitude, and the frequency of reaction chamber cleaning was reduced to 1 / 5 of the original.

[0098] Example 2

[0099] This embodiment refers to the method of embodiment 1, wherein AlCl x (x is 1 to 3), ammonia as aluminum source and nitrogen source, using Figure 1 、 Figure 2 The equipment and supporting process shown in the figure were used to grow AlN single crystals. The results showed that the Figure 2 Equipment comparison Figure 1 The equipment is used to grow AlN single crystals. The effective conversion rate of aluminum into aluminum nitride single crystals has increased from 7.2% to 8.1%, and the conversion rate into polycrystalline aluminum nitride has decreased from 70% to 40%. The recovery rate of metal aluminum has increased from 2% to 29%, and the frequency of equipment cleaning and maintenance has also been reduced to 1 / 4 of the original frequency. Figure 2 The yield and quality (mainly reflected in the surface defect density) of AlN single crystals grown by the equipment and its supporting process are significantly better than those of Figure 1 The AlN single crystals grown by the equipment shown and its supporting process have also shown significant improvements in the recovery ratio of metallic aluminum.

[0100] An embodiment of the present invention provides a method for growing III-V compound single crystals by hydride vapor phase epitaxy, which improves the yield and purity of III-V compound single crystals. In addition, the present invention reduces the formation of III-V compound polycrystals through precise control of multiple regions (temperature and length), dilution gas assistance, and local heating. At the same time, it also achieves high-purity centralized recovery of multiple valuable by-products, reduces recovery costs, and reduces the frequency of equipment maintenance.

[0101] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A method for growing III-V compound single crystals by hydride vapor phase epitaxy, characterized in that include: A first source material and a second source material are introduced into a reaction chamber, wherein the first source material comprises a Group III element and the second source material comprises a Group V element. By setting a first region, a second region, and a third region in the reaction chamber to different temperatures, the first source material and the second source material react in the first region of the reaction chamber to produce a Group III-V compound single crystal and a first by-product, and at least a portion of the first by-product reacts with unreacted first source material in the second region to produce a recyclable Group III element single substance and a second by-product, and at least a portion of the first by-product and / or at least a portion of the second by-product reacts with unreacted second source material in the third region to produce a recyclable product. The first region includes a Group III-V compound single crystal growth region and a peripheral region radially surrounding the Group III-V compound single crystal growth region. The Group III-V compound single crystal growth region is set to a temperature suitable for growing a Group III-V compound single crystal, the temperature of the peripheral region is higher than the temperature of the Group III-V compound single crystal growth region, the temperature of the second region is set to be higher than the formation temperature of the recyclable product and lower than the decomposition temperature of the first source material, and the temperature of the third region is set to be no higher than the decomposition temperature of the recyclable product.

2. The method according to claim 1, characterized in that Also includes: A dilution gas is introduced into the peripheral region to reduce the concentrations of the first source material and the second source material in the peripheral region, thereby preventing the first source material and the second source material from reacting in the peripheral region to generate a III-V compound polycrystal.

3. The method according to claim 2, wherein: At least part of the dilution gas can react with the unreacted first source material in the second region to generate the Group III element; and / or, at least part of the dilution gas can react with the unreacted second source material in the third region to generate the recyclable product.

4. The method according to claim 1, characterized in that Also includes: An operating zone for inserting or removing a growth substrate of a III-V compound single crystal into or from the first zone is provided between the second zone and the third zone, and a temperature of the operating zone is set higher than a generation temperature of the recyclable product.

5. A method for growing a III-nitride single crystal by hydride vapor phase epitaxy, characterized in that include: A group III element source, a nitrogen source, and a carrier gas are introduced into an HVPE reaction chamber and sequentially pass through a first region, a second region, and a third region within the reaction chamber, wherein the first region includes a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, a substrate is distributed within the group III nitride single crystal growth region, the group III element source includes a group III element halide, and the nitrogen source includes NH3; Setting the temperature of the group III nitride single crystal growth region to a first temperature so that a group III element source and a nitrogen source undergo a first reaction in the group III nitride single crystal growth region to generate a group III nitride single crystal, hydrogen, and a halogen hydride, and depositing the group III nitride single crystal on a substrate, and setting the temperature of the peripheral region to a second temperature, wherein the first temperature is a temperature suitable for growing the group III nitride single crystal and the second temperature is greater than the first temperature; Setting the temperature of the second region to a third temperature so that at least the hydrogen generated by the first reaction reacts with the source of the group III element in the second region to generate a simple substance of the group III element and a halogen hydride, wherein the third temperature is higher than a formation temperature of the ammonium salt and lower than a cracking temperature of the halide of the group III element; The temperature of the third region is set to a fourth temperature so that at least the halogen hydride generated by the first reaction and / or the second reaction reacts with the nitrogen source in the third region to generate ammonium salt. The fourth temperature is not higher than the decomposition temperature of the ammonium salt.

6. The method according to claim 5, characterized in that: The peripheral area is an area near the tube wall of the HVPE reaction chamber.

7. The method according to claim 5, characterized in that Specifically include: The temperature of the peripheral zone is set to the second temperature by adjusting the heating power of the HVPE reaction equipment for the peripheral zone; or, the temperature of the peripheral zone is set to the second temperature by providing an auxiliary heating device in the peripheral zone.

8. The method according to claim 5, characterized in that Also includes: A dilution gas is introduced into the peripheral region to reduce the concentrations of the Group III element source and the nitrogen source in the peripheral region.

9. The method according to claim 8, characterized in that: The dilution gas contains hydrogen, and the hydrogen derived from the dilution gas also participates in the second reaction.

10. The method according to claim 9, characterized in that: The input flow rate of the hydrogen is 0.5-50 slm.

11. The method according to claim 9, wherein: The dilution gas contains halogen hydride, and the halogen hydride derived from the dilution gas also participates in the third reaction.

12. The method according to claim 11, wherein: The input flow rate of the halogen hydride is less than the generation rate of the halogen hydride in the first reaction.

13. The method according to claim 12, wherein: The input flow rate of the halogen hydride is 0.05-1slm.

14. The method according to claim 11, wherein: The method comprises: maintaining the hydrogen concentration in the HVPE reaction chamber at 20%-80% and the halogen hydride concentration at 1%-10%.

15. The method according to claim 5, characterized in that: The nitrogen source input into the HVPE reaction chamber is in excess.

16. The method according to claim 5, wherein: The HVPE reaction chamber further includes an operating zone distributed between the second area and the third area, and the temperature of the operating zone is set to be higher than the formation temperature of the ammonium salt.

17. The method according to claim 5, characterized in that Also includes: A group III element simple substance collecting mechanism is provided in the second region.

18. The method according to claim 17, wherein: The group III element simple substance collecting mechanism includes a group III element simple substance collecting plate.

19. The method according to claim 5, wherein: The Group III element source includes GaM x 、InM x 、AlM x or BM x , x ranges from 1 to 3, and M includes Cl, Br or I.

20. An apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy, characterized in that include: An HVPE reaction chamber, the HVPE reaction chamber comprising a first region, a second region, and a third region sequentially connected along a preset direction, wherein the first region comprises a group III nitride single crystal growth region and a peripheral region radially surrounding the group III nitride single crystal growth region, the group III nitride single crystal growth region being capable of at least allowing a group III element source and a nitrogen source to react to generate a group III nitride single crystal, hydrogen, and a halogen hydride; a group III element simple substance collection mechanism being disposed in the second region and capable of allowing a group III element source and hydrogen to react to generate a group III element simple substance and a halogen hydride; and the third region being capable of allowing a nitrogen source and a halogen hydride to react to generate an ammonium salt; A heating device is used at least to respectively make the temperatures of the III-nitride single crystal growth region, the peripheral region, the second region, and the third region reach a first temperature, a second temperature, a third temperature, and a fourth temperature.

21. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 20, characterized in that Also includes: A dilution gas supply mechanism is connected to the HVPE reaction chamber and is used to at least input dilution gas into the peripheral area to reduce the concentration of the Group III element source and the nitrogen source in the peripheral area. The peripheral area is the area near the tube wall of the HVPE reaction chamber.

22. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 20 or 21, characterized in that: A group III element simple substance collecting mechanism is provided in the second region.

23. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 22, wherein: The group III element simple substance collecting mechanism includes a group III element simple substance collecting plate.

24. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 20 or 21, characterized in that: The HVPE reaction chamber further includes an operation area distributed in the second area and the third area. The operation area is provided with an operation port, and an operation cover that can be opened and closed is provided at the operation port.

25. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 20 or 21, characterized in that: The ratio of the lengths of the first region, the second region and the third region is 1:2:2-1:10:

4.

26. The apparatus for growing a III-nitride single crystal by hydride vapor phase epitaxy according to claim 20 or 21, characterized in that: The equipment further comprises a tail gas treatment mechanism, which is connected to the tail gas outlet of the HVPE reaction chamber.

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