Novel gallium nitride reaction chamber heating structure and use method thereof

Abstract

The invention discloses a novel gallium nitride reaction chamber heating structure and a use method thereof. The novel gallium nitride reaction chamber heating structure comprises a high-temperature furnace (103), a carrying table (106) and a gallium boat (101), the thermocouple A (102) is arranged on the side wall of the high-temperature furnace and is used for detecting the temperature in the furnace; the quartz cover (104) covers the lower part of the gallium boat and the carrying platform so as to form a reaction chamber; the manipulator (108) is mounted at the bottom of the high-temperature furnace, and the top of the manipulator bears the carrying table; the thermocouple B (109) is arranged in the manipulator and is used for detecting the temperature of the carrying platform; and the resistance wire (110) is mounted at the top of the manipulator and is used for heating the carrying table. The method has the beneficial effects that the corrosion of the pipe wall of the gas outlet of the gallium boat can be effectively reduced, the service life of the gallium boat is prolonged, the epitaxial film defects are reduced, and the single crystal growth quality is improved.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of semiconductor materials, and more particularly, to a gallium nitride reaction chamber heating structure and methods of using the same. BACKGROUND

[0002] Wide bandgap semiconductor materials such as GaN, SiC, diamond and ZnO are called the third generation of semiconductors, which have excellent properties such as greater breakdown voltage, smaller dielectric constant, higher saturated electron drift velocity, better heat conduction performance, and wider energy gap (Eg≥2.3eV). Among them, GaN is very suitable for making high-frequency, high-power and high-density integrated electronic devices due to its more stable chemical properties, high temperature resistance and corrosion resistance.

[0003] Because the gallium boat in the HVPE device is made of quartz material, under the conditions of high temperature and H2 atmosphere, the gallium boat will be slowly etched, especially under the influence of high temperature, the etching of the pipe wall of the gas outlet at the lower end of the gallium boat is very serious (the temperature of the pipe wall of the gas outlet is higher than that of the main body of the gallium boat), and the serious etching of the gallium boat will cause the precipitation of impurities such as water and oxygen in it, affecting the normal growth of gallium nitride single crystal. Quartz (SiO2) reacts with H2 to generate volatile substances in a high-temperature environment: reaction mechanism: SiO2+2H2→SiO↑+2H2O↑, or further generate silane (SiH4). This process causes the continuous erosion of the quartz surface and the destruction of the structural integrity. The higher the temperature, the faster the reaction rate. The HVPE process usually needs to maintain a high temperature of 1000-1100℃ to activate the reaction of GaCl3 and NH3, which aggravates the corrosion of H2 to quartz. The temperature difference of different parts of the gallium boat and the gas kinetic behavior amplify the corrosion effect: the upper end of the gallium boat is close to the heat source, the temperature is uniform; the lower end of the gas outlet pipe is far away from the heat source and contacts the low-temperature substrate support, the temperature is lower.

[0004] CN112239889B discloses a method for reducing the deposition of gallium nitride on the wall of a halide vapor phase epitaxy system and the halide vapor phase epitaxy system, which comprises a first HCl conduit, a N2 conduit and a NH3 conduit, the first HCl conduit being connected to the gallium boat, and a second HCl conduit being connected to a position close to the outlet of the gallium boat region. The halide vapor phase epitaxy system comprising the gas path system and the method for reducing the deposition of gallium nitride on the wall of the halide vapor phase epitaxy system are also disclosed. A route of HCl is added to the gallium boat region close to the outlet, and the GaCl mixed after reaction in the low temperature zone is transported again. When the HCl and GaCl mixed gas pass through the quartz tube at the outlet, the HCl will corrode the pre-reacted GaN deposited on the wall of the tube, thereby reducing the deposition on the wall, so that the growth rate and uniformity will not decrease significantly due to the reduction of the inner diameter of the tube. The corrosion reaction product is GaCl, which can also increase the concentration of the reactants transported above the substrate, maintain the long-time high stability of the GaN growth on the substrate, and improve the utilization rate of gallium. The patent aims to solve the problem of reducing the deposition of GaN on the inner wall of the quartz tube at the GaCl outlet.

[0005] CN214361833U discloses a gallium boat structure for reducing defects of HVPE epitaxial film, which comprises a shell 1, an upper flange end 2 sealedly mounted on the upper end of the shell, a gas inlet pipe 3 communicated with the center of the upper flange end, a first gas inlet 4 and a second gas inlet 5 symmetrically arranged on the upper flange end with respect to the gas inlet pipe, a multi-layer tank 6 fixedly connected to the bottom of the upper flange end for containing metallic gallium, a contraction part 7 provided at the bottom of the multi-layer tank, a cylindrical cavity formed by the bottom of the gas inlet pipe extending downward along the axial direction of the multi-layer tank and concentric with the contraction part, a support 8 located below the multi-layer tank in the shell, and a substrate 9 placed on the support and facing the cylindrical cavity. The patent solves the problem of quartz tube corrosion by modifying the lower end of the quartz tube into a detachable quartz tube, which can be replaced in time when the gas corrosion is serious. However, this is a post-treatment and does not completely eliminate the corrosion from the root. SUMMARY

[0006] The present application aims to design a new heating structure, in which the HVPE equipment is heated by a high-temperature furnace and a heating support instead of the original high-temperature furnace (the high-temperature furnace is divided into six temperature zones, and each temperature zone is set to a temperature according to its function). At this time, the temperature of the six temperature zones of the high-temperature furnace is set uniformly, and the temperature is the reaction temperature of Ga and HCl, which is relatively low. The temperature of the heating support is controlled separately, and the temperature is the reaction temperature of GaCl3 and NH3, which is relatively high. This heating structure can reduce the etching rate of the gallium boat, especially the etching rate of the outlet tube wall of the gallium boat, thereby improving the service life of the gallium boat and reducing the defects of gallium nitride, so as to achieve the purpose of reducing cost and increasing benefit.

[0007] The technical scheme of the present application is: a novel gallium nitride reaction chamber heating structure, comprising: a high-temperature furnace, a carrier and a gallium boat; further comprising: a thermocouple A installed on the side wall of the high-temperature furnace for detecting the temperature in the furnace; a quartz cover that covers the lower part of the gallium boat and the carrier to form a reaction chamber; a mechanical hand installed at the bottom of the high-temperature furnace and carrying the carrier at the top; a thermocouple B installed inside the mechanical hand for detecting the temperature of the carrier; and a resistance wire installed at the top of the mechanical hand for heating the carrier.

[0008] The improvement of the above scheme is that the mechanical hand is surrounded by an inner liner and an outer liner in the form of a ring, and the height of the inner liner is lower than that of the outer liner.

[0009] In the above scheme, the heating temperature of the resistance wire is 1000-1200℃.

[0010] In the above scheme, the thermocouple A has six, which are distributed along the height direction of the high-temperature furnace.

[0011] In the above scheme, the temperature measuring range of the thermocouple A is 800-900℃.

[0012] A novel gallium nitride reaction chamber heating structure and its use method, comprising the following steps: controlling the temperature of the high-temperature furnace at 800-900℃ by the thermocouple A, and controlling the heating temperature of the resistance wire heating at 1000-1200℃ by the thermocouple B, so as to reduce the corrosion of the outlet of the gallium boat.

[0013] The beneficial effect of the present application is that by changing the heating structure of the reaction chamber, the etching rate of the gallium boat, especially the etching rate of the outlet pipe wall of the gallium boat, can be slowed down, the service life of the gallium boat is improved, and the quality of single crystal growth is improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structural diagram of a novel gallium nitride reaction chamber heating structure of the present application; Figure 2 is a physical map of the corroded part of the gallium boat after use; In the figure, 101 is a gallium boat, 102 is a thermocouple A, 103 is a heating furnace, 104 is a quartz cover, 105 is an outer liner, 106 is a carrier, 107 is an inner liner, 108 is a mechanical hand, 109 is a thermocouple B, 110 is a resistance wire, 201 is the upper half of the gallium boat outlet, and 102 is the lower half of the gallium boat outlet. DETAILED DESCRIPTION

[0015] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] like Figure 2 As shown, the testable temperature range of the thermocouple A is 0°C-1450°C. It is installed on the heating furnace, and there are 6 of them from top to bottom, measuring the temperatures of 6 temperature zones. The temperature setting range of the first temperature zone is 800-1000°C, the temperature setting range of the second temperature zone is 800-1000°C, the temperature setting range of the third temperature zone is 1000-1200°C, the temperature setting range of the fourth temperature zone is 1000-1200°C, the temperature setting range of the fifth temperature zone is 1000-1200°C, and the temperature setting range of the sixth temperature zone is 1000-1200°C. The heating furnace provides the reaction temperature, and the temperature in the furnace can reach up to 1200°C. The quartz cover will reflect The reaction chamber is isolated from the outside world, creating a high-quality reaction environment. The gallium boat, located at the upper end of the reaction chamber, holds gallium metal. Special gases enter through the boat's inlet and react with gallium, with the products exiting through the boat's outlet and deposited on the substrate surface of the carrier. The carrier is located at the top of the manipulator, which holds the substrate required for wafer growth. The reaction products are deposited on the carrier substrate surface. The manipulator, located at the lower end of the reaction chamber, can be raised and lowered. A thermocouple B is installed inside the manipulator to measure the temperature of the resistance wire during heating. The resistance wire is installed at the upper end of the manipulator, at the bottom of the carrier, and connected to a graphite electrode for heating the bottom of the carrier. After a period of use, the upper half 201 of the gallium boat's outlet appears transparent and free of white spots, while the lower half 202 of the gallium boat's outlet exhibits numerous small white spots, creating visible etching marks. Etching by the gallium boat can also lead to the precipitation of impurities such as water and oxygen on the wafer surface, affecting the growth and quality of gallium nitride single crystals. Under the same atmosphere, two different situations occur. The difference lies in the temperature. The temperature range of the upper half of the gallium boat outlet is 800℃-1000℃, and the temperature range of the lower half of the gallium boat outlet is 1000℃-1200℃.

[0017] Thermodynamic analysis Reaction equation: SiO2(s) + H2(g) → SiO(g) + H2O(g) The Gibbs free energy (ΔG) of this reaction changes with decreasing temperature. At 800-1000°C, ΔG remains negative, but its absolute value is smaller than that at 1000-1200°C, resulting in a weakening of the reaction driving force.

[0018] Dynamic factors Temperature influence: Temperature decreases by about 200℃, the reaction rate constant (k) will be significantly reduced (follow the Arrhenius equation), resulting in a significant slowdown in corrosion rate.

[0019] Example: If the activation energy is 150 kJ / mol, the temperature decreases from 1373K to 1173K, the rate decreases by about an order of magnitude.

[0020] The temperature of the heating furnace of the present application is set uniformly, the temperature setting range of the six temperature zones is 800-1000℃, the temperature setting range of the resistance wire is 1000-1200℃, and the temperature is tested by a thermocouple. The special gas HCl reacts with the metal gallium in the gallium boat to generate gallium chloride, and the gallium chloride reacts with the special gas NH3 to generate gallium nitride deposited on the surface of the substrate. The substrate is placed on the stage.

[0021] As shown in Figure 1 A new gallium nitride reaction chamber heating structure, comprising: a high temperature furnace 103, a stage 106 and a gallium boat 101; further comprising: a thermocouple A 102, the thermocouple A is installed on the side wall of the high temperature furnace for detecting the temperature in the furnace; a quartz cover 104, which covers the lower part of the gallium boat and the stage to form a reaction chamber; a mechanical hand 108, which is installed at the bottom of the high temperature furnace and carries the stage at the top; a thermocouple B 109, which is installed inside the mechanical hand for detecting the temperature of the stage; a resistance wire 110, which is installed at the top of the mechanical hand for heating the stage. The thermocouple A has six, which are distributed along the height direction of the high temperature furnace.

[0022] The present application shows that by changing the heating structure of the reaction chamber, the temperature of the gallium boat exhaust port is reduced, the etching rate of the gallium boat exhaust port tube wall is slowed down, the service life of the gallium boat is improved, and the epitaxial film defects are reduced, thereby improving the quality of single crystal growth.

Claims

1. A novel gallium nitride reaction chamber heating structure, comprising: A high-temperature furnace (103), a carrier (106) and a gallium boat (101); characterized in that it also includes: a thermocouple A (102), the thermocouple A being installed on the side wall of the high-temperature furnace for detecting the temperature inside the furnace; a quartz cover (104), the quartz cover covering the lower part of the gallium boat and the carrier to form a reaction chamber; a manipulator (108), the manipulator being installed at the bottom of the high-temperature furnace and carrying the carrier on the top; a thermocouple B (109), the thermocouple B being installed inside the manipulator for detecting the temperature of the carrier; and a resistance wire (110), the resistance wire being installed on the top of the manipulator for heating the carrier.

2. The novel gallium nitride reaction chamber heating structure according to claim 1, characterized in that: The outside of the manipulator is surrounded by an annular inner lining (107) and an outer lining (105), and the height of the inner lining is lower than that of the outer lining.

3. The novel gallium nitride reaction chamber heating structure according to claim 1, characterized in that: The heating temperature of the resistance wire is 1000°C-1200°C.

4. The novel gallium nitride reaction chamber heating structure according to claim 1, characterized in that: There are six thermocouples A, which are distributed at intervals along the height direction of the high-temperature furnace.

5. The novel gallium nitride reaction chamber heating structure according to claim 1, characterized in that: The temperature measuring range of the thermocouple A is 800°C-900°C.

6. The method for using the novel gallium nitride reaction chamber heating structure according to claim 1, wherein: The following steps are involved: The temperature of the high-temperature furnace is controlled at 800-900°C by thermocouple A, and the temperature of the resistance wire heating is controlled at 1000-1200°C by thermocouple B to reduce corrosion of the gas outlet of the gallium boat.

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