Device and method for growing nitride crystals by regulating and controlling temperature gradient

Abstract

The invention provides a device and method for growing nitride crystals by regulating and controlling temperature gradient, and belongs to the technical field of semiconductor synthesis, the device comprises a low-temperature reaction zone and a high-temperature crystallization zone, heaters are arranged on the outer sides of the low-temperature reaction zone and the high-temperature crystallization zone, a temperature field is constructed in the high-temperature crystallization zone, and the temperature gradient of the temperature field is adjusted and controlled. The low-temperature reaction area is provided with a first gas inlet pipe, a second gas inlet pipe and a reaction boat, the tail end of the first gas inlet pipe is communicated with the reaction boat, the tail end of the second gas inlet pipe is communicated with the high-temperature crystallization area, the high-temperature crystallization area is provided with a seed crystal fixing support, and the seed crystal fixing support is fixedly arranged on a seed crystal fixing rod. The temperature field with the temperature gradient is constructed by adjusting the structure of the cavity in the high-temperature crystallization area or adjusting the arrangement mode of the heaters on the outer side of the high-temperature crystallization area, repeatability is good, the growth efficiency of the nitride bulk crystals is improved by controlling the axial temperature gradient and the radial temperature gradient, and the growth quality is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of semiconductor synthesis technology, and more specifically to an apparatus and method for growing nitride crystals by controlling a temperature gradient. Background Technology

[0002] Nitride crystals belong to the third generation of semiconductor materials. They have characteristics such as large band gap, high thermal conductivity, high breakdown electric field, low dielectric constant, high electron saturation drift velocity, better chemical stability, and strong radiation resistance. They have great application potential in light-emitting devices such as blue diodes, blue lasers, and ultraviolet detectors, as well as high-temperature, high-frequency, and high-power microelectronic devices.

[0003] Hydride epitaxy (HVPE) is currently the mainstream growth technology for preparing nitride crystals. It does not require ultra-high temperature and ultra-high pressure growth conditions, has low requirements for production equipment, and offers advantages such as fast growth rate and easy doping. The basic principle of HVPE for growing nitride crystals is as follows: in the low-temperature reaction zone, a metal source reacts with hydrogen chloride gas to generate metal chloride. Subsequently, the metal chloride is transported by high-purity nitrogen gas to the high-temperature crystallization zone where it reacts with ammonia gas, depositing onto a seed crystal to prepare the nitride crystal. Bulk nitride crystal growth requires a certain temperature gradient. However, most current HVPE reactors operate in isothermal zones for both the low-temperature reaction zone and the high-temperature crystallization zone. While some HVPE reactors utilize induction heating to achieve a temperature gradient in the high-temperature crystallization zone, this method suffers from poor repeatability, resulting in low growth efficiency and inconsistent crystal quality when growing bulk nitride crystals.

[0004] Therefore, we propose an apparatus and method for growing nitride crystals by controlling the temperature gradient. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for growing nitride crystals by controlling a temperature gradient, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an apparatus for growing nitride crystals by controlling a temperature gradient, comprising a cavity, the cavity comprising a low-temperature reaction zone and a high-temperature crystallization zone connected in sequence, wherein a plurality of heaters for heating are provided on the outer side of both the low-temperature reaction zone and the high-temperature crystallization zone, wherein a temperature field with an axial temperature gradient and a radial temperature gradient is constructed in the high-temperature crystallization zone, wherein the low-temperature reaction zone is provided with a first inlet pipe for introducing hydrogen chloride gas or chlorine gas, a second inlet pipe for introducing ammonia gas, and a reaction boat, wherein the end of the first inlet pipe is connected to the reaction boat, and the end of the second inlet pipe is connected to the high-temperature crystallization zone through an outlet, wherein the hydrogen chloride gas or chlorine gas in the first inlet pipe reacts with the metal in the reaction boat to generate an intermediate product, and the intermediate product is connected to the high-temperature crystallization zone through an intermediate pipeline; The high-temperature crystallization zone is equipped with a seed crystal fixing support, which is fixedly mounted on the seed crystal fixing rod. Ammonia and intermediate products in the second gas tube react at the seed crystal fixing support to generate nitrides. The area within 0-2 cm to the left of the seed crystal fixing support is the crystal growth area.

[0007] Preferably, the gas outlet includes an ammonia gas outlet and an intermediate product gas outlet. The ammonia gas outlet and the intermediate product gas outlet are not connected. The ammonia gas outlet is connected to the end of the second gas inlet pipe, and the intermediate product gas outlet is connected to the end of the intermediate pipeline.

[0008] Preferably, the cavity located in the high-temperature crystallization zone includes a first pipe segment, a second pipe segment, and a third pipe segment connected in sequence. The axial diameter of the second pipe segment is smaller than that of the first and third pipe segments. The axial diameter of the first pipe segment gradually decreases at the end near the second pipe segment. The axial diameter of the second pipe segment is the same. The axial diameter of the third pipe segment gradually decreases at the end near the second pipe segment.

[0009] Preferably, the seed crystal fixing support is located at the second section of the cavity in the high-temperature crystallization zone.

[0010] Preferably, the spacing between the heaters located on the left side of the seed crystal fixing holder is smaller than the spacing between the heaters located on the right side of the seed crystal fixing holder.

[0011] Preferably, the axial temperature gradient of the temperature field in the crystal growth region is 0.5-10℃ / cm, and the radial temperature gradient of the temperature field in the crystal growth region is 0.5-2℃ / cm.

[0012] Preferably, the heater has an insulation layer on its outer side for heat preservation.

[0013] In a second aspect, the present invention provides a method for growing nitride crystals by controlling a temperature gradient, the method using the apparatus for growing nitride crystals by controlling a temperature gradient as described in the first aspect, comprising the following steps: S1: Fix the seed crystal on the seed crystal holder and place it in the high-temperature crystallization zone, so that the distance between the seed crystal and the gas outlet is 1-10cm; S2: Heat the low-temperature reaction zone and the high-temperature crystallization zone to the required temperature, control the axial temperature gradient of the temperature field in the crystal growth zone to be 0.5-10℃ / cm, and control the radial temperature gradient of the temperature field in the crystal growth zone to be 0.5-2℃ / cm. During the heating process, carrier gas and ammonia are continuously introduced. S3: After the temperatures of the low-temperature reaction zone and the high-temperature crystallization zone stabilize, hydrogen chloride gas is introduced. The hydrogen chloride gas reacts with the metal in the reaction boat in the low-temperature reaction zone to generate intermediate products. The intermediate products are transported to the high-temperature crystallization zone by the carrier gas. The intermediate products react with ammonia gas at the seed crystal fixing holder to generate nitrides. The nitride growth time is at least 50 hours. S4: After the nitride growth is complete, stop the flow of hydrogen chloride gas and start cooling the high-temperature crystallization zone. When the temperature drops to the maintenance temperature of the low-temperature reaction zone, stop the flow of ammonia gas. After the low-temperature reaction zone and the high-temperature crystallization zone drop to room temperature, remove the nitride that has been grown.

[0014] Preferably, the carrier gas is at least one of N2, H2 and Ar.

[0015] Compared with the prior art, the present invention has the following technical effects: 1. In this invention, a temperature field with axial and radial temperature gradients is formed in the high-temperature crystallization region. The axial temperature gradient of the crystal growth region is controlled to be 0.5-10℃ / cm, and the radial temperature gradient of the temperature field in the crystal growth region is controlled to be 0.5-2℃ / cm. By controlling the axial and radial temperature gradients of the temperature field in the crystal growth region, the growth efficiency of the nitride bulk crystal is improved, and the growth quality of the nitride bulk crystal is guaranteed.

[0016] 2. In this invention, a temperature field with a temperature gradient is constructed by adjusting the structure of the cavity inside the high-temperature crystallization zone or by adjusting the arrangement of the heaters outside the high-temperature crystallization zone. Compared with using induction heating to achieve the temperature gradient in the high-temperature crystallization zone, the repeatability is better. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the apparatus for growing nitride crystals by controlling a temperature gradient according to an embodiment of the present invention; Figure 2 This is another schematic diagram of the apparatus for growing nitride crystals by controlling the temperature gradient according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a self-peeling native surface gallium nitride substrate according to an embodiment of the present invention; Figure 4This is a surface morphology diagram of a 3mm gallium nitride bulk crystal according to an embodiment of the present invention; Figure 5 This is a surface morphology diagram of a 6mm gallium nitride bulk crystal according to an embodiment of the present invention; Figure 6 This is a surface morphology diagram of an aluminum nitride single-crystal thin film according to an embodiment of the present invention.

[0018] In the diagram: 1. Cavity; 2. Low-temperature reaction zone; 3. High-temperature crystallization zone; 4. Reaction boat; 5. First inlet pipe; 6. Intermediate pipe; 7. Second inlet pipe; 8. Heater; 9. Insulation layer; 10. Gas outlet; 101. Ammonia gas outlet; 102. Gallium chloride gas outlet; 11. Seed crystal fixing support; 12. Seed crystal fixing rod; 13. First pipe section; 14. Second pipe section; 15. Third pipe section. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention. In this article, terms such as "left," "right," "up," "down," "front," and "back" are established based on the positional relationships shown in the attached drawings. Depending on the attached drawings, the corresponding positional relationships may also change. Therefore, they should not be interpreted as an absolute limitation on the scope of protection.

[0020] Please see Figures 1 to 2 This invention provides an apparatus for growing nitride crystals by controlling a temperature gradient, comprising a cavity 1. The material of the cavity 1 can be selected according to the reaction temperatures of the low-temperature reaction zone 2 and the high-temperature crystallization zone 3. The cavity 1 includes a low-temperature reaction zone 2 and a high-temperature crystallization zone 3 connected in sequence. Multiple heaters 8 are disposed on the outer side of the low-temperature reaction zone 2 and the high-temperature crystallization zone 3, and the heaters 8 are used to heat the low-temperature reaction zone 2 and the high-temperature crystallization zone 3. A heat insulation layer 9 is provided on the outer side of the heaters 8 to maintain the temperature of the low-temperature reaction zone 2 and the high-temperature crystallization zone 3.

[0021] The length of the high-temperature crystallization region 3 is 50-500 cm, and can be determined according to the type of nitride bulk crystal growth and the actual growth conditions. A temperature field with axial and radial temperature gradients is constructed in the high-temperature crystallization region 3. The area within 0-2 cm to the left of the seed crystal fixing support 11 is the crystal growth region. The axial temperature gradient of the temperature field in the crystal growth region is 0.5-10℃ / cm, that is, the axial temperature gradient for the epitaxial growth of the nitride bulk crystal is 0.5-10℃ / cm, and the radial temperature gradient of the temperature field in the crystal growth region is 0.5-2℃ / cm, that is, the radial temperature gradient for the epitaxial growth of the nitride bulk crystal is 0.5-2℃ / cm. During the growth of the nitride bulk crystal, the axial and radial temperature gradients of the temperature field in the crystal growth region need to be determined according to the type of nitride bulk crystal and the actual growth conditions.

[0022] Taking the growth of gallium nitride bulk crystals as an example, the low-temperature reaction zone 2 is equipped with a first inlet pipe 5, a second inlet pipe 7, and a reaction boat 4. The first inlet pipe 5 is used to introduce hydrogen chloride gas or chlorine gas; in this embodiment, the first inlet pipe 5 is used to introduce hydrogen chloride gas. The second inlet pipe 7 is used to introduce ammonia gas. Metallic gallium is placed in the reaction boat 4. The end of the first inlet pipe 5 is connected to the reaction boat 4. The hydrogen chloride gas in the first inlet pipe 5 reacts with the metallic gallium in the reaction boat 4 to generate gallium chloride gas. The gallium chloride gas is connected to the high-temperature crystallization zone 3 through an intermediate pipe 6. One end of the intermediate pipe 6 is connected to the reaction boat 4, and the other end of the intermediate pipe 6 is connected to the high-temperature crystallization zone 3 through an outlet 10. The end of the second air inlet pipe 7 is connected to the high-temperature crystallization zone 3 via the air outlet 10. A seed crystal fixing support 11 is provided within the high-temperature crystallization zone 3 to fix the seed crystal. The seed crystal fixing support 11 is fixedly mounted on the seed crystal fixing rod 12. Ammonia and gallium chloride gas in the second air inlet pipe 7 react at the seed crystal to generate gallium nitride, and the gallium nitride bulk crystal begins to grow. Furthermore, the placement of the seed crystal fixing support 11 is based on the form of the air outlet 10. The seed crystal fixing support 11 can be placed vertically, horizontally, or obliquely, but it is necessary to ensure uniform airflow at the seed crystal. The axial diameter of the cavity 1 at the seed crystal is 5-100 cm, determined according to the diameter of the crystal.

[0023] The design standard for the gas outlet 10 is to ensure uniform airflow when gallium chloride gas is blown to the seed crystal, and to prevent polycrystalline deposition on the gas outlet 10. The gas outlet 10 is generally of the multi-ring type or nozzle type, but is not limited to these types. In this embodiment, the gas outlet 10 is an integrated design, including an ammonia gas outlet 101 and a gallium chloride gas outlet 102. The ammonia gas outlet 101 and the gallium chloride gas outlet 102 are not connected. The ammonia gas outlet 101 is connected to the end of the second inlet pipe 7, and the gallium chloride gas outlet 102 is connected to the end of the intermediate pipeline 6 away from the reaction boat 4.

[0024] like Figure 1 As shown, the temperature field required for gallium nitride bulk crystal growth is constructed by adjusting the structure of the cavity 1 within the high-temperature crystallization zone 3. The high-temperature crystallization zone 3 is 100 cm long, and the axial diameter of the cavity 1 at the seed crystal is 15 cm, i.e., the axial diameter of the second tube segment 14 is 15 cm. The shapes of the heater 8 and the insulation layer 9 outside the high-temperature crystallization zone 3 are changed according to the shape of the cavity 1. The cavity 1 located in the high-temperature crystallization zone 3 includes a first tube segment 13, a second tube segment 14, and a third tube segment 15 connected in sequence. The axial diameter of the second tube segment 14 is smaller than that of the first tube segment 13 and the third tube segment 15. The axial diameter of the first tube segment 13 gradually decreases towards the end near the second tube segment 14, while the axial diameter of the second tube segment 14 remains the same. The axial diameter of the third tube segment 15 gradually decreases towards the end near the second tube segment 14. This design of the cavity 1 can also play a role in gas concentration and flow guidance, resulting in a higher effective reaction rate within the cavity 1. The seed crystal holder 11 is located at the second segment 14 of the cavity 1 in the high-temperature crystallization zone 3. The axial diameter of the second segment 14 is slightly larger than the diameter of the seed crystal holder 11 to facilitate the flow of growth gas. By adjusting the shape of the cavity 1 in the high-temperature crystallization zone 3, the shapes of the heater 8 and the insulation layer 9 on the outside of the cavity 1 are also changed accordingly, creating a positive axial temperature gradient and a positive radial temperature gradient. This prevents the growth gradient from being negative during the growth of gallium nitride bulk crystals, which would lead to polycrystalline and dendritic growth. At the same time, the presence of positive axial and radial temperature gradients can improve the growth rate of gallium nitride bulk crystals. In addition, the slope of the first segment 13 and the third segment 15, as well as the connection points of each segment, must be smooth.

[0025] like Figure 2 As shown, the temperature field required for gallium nitride bulk crystal growth is constructed by adjusting the arrangement of the heaters 8 on the outer side of the high-temperature crystallization region 3. The spacing between the heaters 8 located to the left of the seed crystal fixing support 11 is small, while the spacing between the heaters 8 located to the right of the seed crystal fixing support 11 is large. By adjusting the spacing between the heaters 8 in the high-temperature crystallization region 3, a positive axial temperature gradient and a positive radial temperature gradient are constructed. This prevents the growth gradient from being negative during the growth of the gallium nitride bulk crystal, which would lead to polycrystalline and dendritic growth. At the same time, the presence of positive axial and radial temperature gradients can improve the growth rate of the gallium nitride bulk crystal.

[0026] By adjusting the structure of the inner cavity 1 of the high-temperature crystallization region 3 or adjusting the arrangement of the heaters 8 on the outer side of the high-temperature crystallization region 3, a temperature field with a temperature gradient is constructed. Compared with using induction heating to achieve the temperature gradient of the high-temperature crystallization region 3, the repeatability is better. In the growth process of gallium nitride bulk crystal, by controlling the axial temperature gradient and radial temperature gradient of the temperature field in the crystal growth region, the growth efficiency of gallium nitride bulk crystal is improved and the growth quality of gallium nitride bulk crystal is guaranteed.

[0027] like Figure 6 As shown, using a sapphire single-crystal substrate, this device also successfully grew AlN single-crystal thin films, providing technical reserves for the growth of bulk AlN crystals.

[0028] Taking gallium nitride crystal growth as an example, using Figure 1 or Figure 2 The present invention also provides a method for preparing gallium nitride bulk crystals by growing nitride crystals through controlling a temperature gradient, as shown in the apparatus.

[0029] S1: A self-peeling native gallium nitride substrate is used as the seed crystal, such as... Figure 3 As shown. The seed crystal is fixed on the seed crystal holder 11, and the fixed seed crystal is placed in the high-temperature crystallization zone 3. The distance between the seed crystal and the gas outlet 10 is 8cm.

[0030] S2: The low-temperature reaction zone 2 and the high-temperature crystallization zone 3 are heated simultaneously. The temperature of the low-temperature reaction zone 2 is increased at a rate of 5℃ / min, and the temperature of the high-temperature crystallization zone 3 is increased at a rate of 3℃ / min. The temperature of the low-temperature reaction zone 2 is set to 850℃, the temperature of the leftmost part of the crystal growth region is 1062℃, and the temperature of the rightmost part of the crystal growth region is 1060℃, that is, the temperature of the substrate seed crystal is 1060℃. The temperature changes uniformly, with an axial temperature gradient of 1℃ / cm and a radial temperature gradient of 1℃ / cm. During the heating process, carrier gas and ammonia are continuously introduced to protect the gallium nitride wafer.

[0031] Specifically, the carrier gas is at least one of N2, H2 and Ar. In this embodiment, the carrier gas is N2.

[0032] S3: After the temperatures of the low-temperature reaction zone 2 and the high-temperature crystallization zone 3 stabilize, hydrogen chloride gas is introduced. The hydrogen chloride gas reacts with the metallic gallium in the reaction boat 4 in the low-temperature reaction zone 2 to generate gallium chloride gas. The gallium chloride gas is transported to the high-temperature crystallization zone 3 by the carrier gas. The gallium chloride gas reacts with ammonia gas at the seed crystal fixing holder 11 to generate gallium nitride. Gallium nitride is epitaxially grown at the seed crystal. The axial temperature gradient of gallium nitride epitaxial growth is 1℃ / cm, the radial temperature gradient of gallium nitride epitaxial growth is 1℃ / cm, and the epitaxial growth time is 60h.

[0033] Specifically, the growth time of gallium nitride crystals is determined by the deposition of reaction byproducts. If there are few byproducts, the growth time of gallium nitride crystals can reach 100 hours or even longer.

[0034] S4: After gallium nitride growth is complete, stop the flow of hydrogen chloride gas and start cooling the high-temperature crystallization zone 3. When the temperature drops to the stable temperature of the low-temperature reaction zone 2, stop the flow of ammonia gas. After the low-temperature reaction zone 2 and the high-temperature crystallization zone 3 have cooled to room temperature, remove the grown gallium nitride block crystal.

[0035] By controlling the axial and radial temperature gradients during gallium nitride epitaxial growth, bulk gallium nitride crystals were fabricated, such as... Figure 4 and Figure 5 As shown, the crystal thickness is between 3 and 6 mm.

[0036] A temperature field with axial and radial temperature gradients is formed in the high-temperature crystallization zone 3. By controlling the axial and radial temperature gradients of the temperature field in the crystal growth region, the growth efficiency of the nitride bulk crystal is improved and the growth quality of the nitride bulk crystal is guaranteed.

[0037] The above embodiments merely illustrate the basic principles and characteristics of the present invention, but are not limited to the above implementation schemes. It should be understood that those skilled in the art can make various changes and modifications to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An apparatus for growing nitride crystals by controlling a temperature gradient, characterized in that, The system includes a cavity (1), which includes a low-temperature reaction zone (2) and a high-temperature crystallization zone (3) connected in sequence. Both the low-temperature reaction zone (2) and the high-temperature crystallization zone (3) are provided with multiple heaters (8) for heating. The high-temperature crystallization zone (3) is constructed with a temperature field having an axial temperature gradient and a radial temperature gradient. The low-temperature reaction zone (2) is provided with a first inlet pipe (5) for introducing hydrogen chloride gas or chlorine gas, a second inlet pipe (7) for introducing ammonia gas, and a reaction boat (4). The end of the first inlet pipe (5) is connected to the reaction boat (4), and the end of the second inlet pipe (7) is connected to the high-temperature crystallization zone (3) through an outlet (10). The hydrogen chloride gas or chlorine gas in the first inlet pipe (5) reacts with the metal in the reaction boat (4) to generate an intermediate product. The intermediate product is connected to the high-temperature crystallization zone (3) through an intermediate pipeline (6). The high-temperature crystallization zone (3) is provided with a seed crystal fixing holder (11), which is fixedly mounted on the seed crystal fixing rod (12). The ammonia gas and intermediate products in the second air inlet pipe (7) react at the seed crystal fixing holder (11) to generate nitrides. The area within 0-2cm to the left of the seed crystal fixing holder (11) is the crystal growth area.

2. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 1, characterized in that, The outlet (10) includes an ammonia outlet (101) and an intermediate product outlet. The ammonia outlet (101) and the intermediate product outlet are not connected. The ammonia outlet (101) is connected to the end of the second inlet pipe (7). The intermediate product outlet is connected to the end of the intermediate pipeline (6).

3. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 1, characterized in that, The cavity (1) located in the high-temperature crystallization zone (3) includes a first pipe section (13), a second pipe section (14) and a third pipe section (15) connected in sequence. The shaft diameter of the second pipe section (14) is smaller than that of the first pipe section (13) and the third pipe section (15). The shaft diameter of the first pipe section (13) gradually decreases at the end near the second pipe section (14). The shaft diameter of the second pipe section (14) is the same. The shaft diameter of the third pipe section (15) gradually decreases at the end near the second pipe section (14).

4. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 3, characterized in that, The seed crystal fixing holder (11) is located at the second tube section (14) of the cavity (1) in the high temperature crystallization zone (3).

5. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 1, characterized in that, The spacing between the heaters (8) located on the left side of the seed crystal fixing holder (11) is smaller than the spacing between the heaters (8) located on the right side of the seed crystal fixing holder (11).

6. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 3 or 5, characterized in that, The axial temperature gradient of the temperature field in the crystal growth region is 0.5-10℃ / cm, and the radial temperature gradient of the temperature field in the crystal growth region is 0.5-2℃ / cm.

7. The apparatus for growing nitride crystals by controlling a temperature gradient according to claim 1, characterized in that, The heater (8) is provided with an insulation layer (9) for heat preservation on the outside.

8. A method for growing nitride crystals by controlling a temperature gradient, characterized in that, The method uses the apparatus for growing nitride crystals by controlling a temperature gradient as described in any one of claims 1-7, and includes the following steps: S1: Fix the seed crystal on the seed crystal holder (11) and place it in the high temperature crystallization zone (3) so that the distance between the seed crystal and the gas outlet (10) is 1-10cm; S2: Heat the low-temperature reaction zone (2) and the high-temperature crystallization zone (3) to the required temperature, control the axial temperature gradient of the temperature field in the crystal growth zone to be 0.5-10℃ / cm, and control the radial temperature gradient of the temperature field in the crystal growth zone to be 0.5-2℃ / cm. During the heating process, carrier gas and ammonia are continuously introduced. S3: After the temperatures of the low-temperature reaction zone (2) and the high-temperature crystallization zone (3) stabilize, hydrogen chloride gas is introduced. The hydrogen chloride gas reacts with the metal in the reaction boat (4) in the low-temperature reaction zone (2) to generate intermediate products. The intermediate products are transported to the high-temperature crystallization zone (3) by the carrier gas. The intermediate products react with ammonia at the seed crystal fixing holder (11) to generate nitrides. The nitride growth time is at least 50 hours. S4: After the nitride growth is complete, stop the flow of hydrogen chloride gas and start cooling the high-temperature crystallization zone (3). When the temperature drops to the stable temperature of the low-temperature reaction zone (2), stop the flow of ammonia gas. When the low-temperature reaction zone (2) and the high-temperature crystallization zone (3) drop to room temperature, take out the nitride that has been grown.

9. The method for growing nitride crystals by controlling a temperature gradient according to claim 8, characterized in that, The carrier gas is at least one of N2, H2 and Ar.

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