Silicon carbide chemical vapor deposition reaction apparatus and method

Abstract

The application relates to a silicon carbide chemical vapor deposition reaction device and method. The application specifically comprises a flow guide cavity and a crystal growth cavity, the flow guide cavity is provided with a first gas channel and a first heating element, the first gas channel extends in a bent shape, and the first heating element is uniformly distributed on the inner wall of the first gas channel; the crystal growth cavity is provided with a second gas channel and a second heating element, and the second heating element is uniformly distributed on the inner wall of the second gas channel. The first gas channel of the application extends in a bent shape, thereby prolonging the time for the reaction gas to flow through the first gas channel, and the first heating element is uniformly distributed on the inner wall of the first gas channel, thereby generating a uniform heat field in the first gas channel, improving the pyrolysis rate of the reaction precursor gas, and further improving the preparation efficiency of the silicon carbide epitaxial layer crystal and the preparation quality of the silicon carbide epitaxial layer crystal.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material forming technology, and in particular to a silicon carbide chemical vapor deposition reaction apparatus and method. Background Technology

[0002] Silicon carbide (SiC) is a high-performance semiconductor material with characteristics such as high thermal conductivity, high critical breakdown field strength, and high saturated electron drift velocity. It is widely used in cutting-edge technological fields such as power electronics and new energy vehicles. Before fabricating SiC using SiC materials, an epitaxial process is typically performed on a SiC substrate to prepare a high-quality SiC epitaxial layer crystal. Chemical vapor deposition (CVD) is a commonly used method for preparing SiC epitaxial layer crystals.

[0003] Equipment used for preparing silicon carbide epitaxial crystals by chemical vapor deposition typically includes planetary deposition equipment, vertical deposition equipment, and horizontal deposition equipment. Regardless of whether planetary deposition equipment, vertical deposition equipment, horizontal deposition equipment, or other types of chemical vapor deposition equipment are used, the process involves mixing the precursor gas and the carrier gas and then introducing them into the reaction chamber, where the precursor gas decomposes and deposits on the silicon carbide substrate.

[0004] When using ethylene (C2H4) or propane (C3H8) and silane (SiH4) as the reaction precursor gas and hydrogen (H2) as the carrier gas, a process temperature above 1700K is typically required. However, in the growth of large-size (e.g., 8-inch or 12-inch) silicon carbide epitaxial layers, excessively high process temperatures can exacerbate thermal stress accumulation between the large-size silicon carbide epitaxial layer and the silicon carbide substrate due to factors such as the difference in thermal expansion coefficients. Furthermore, it carries the risk of increasing the warpage of the silicon carbide substrate, thereby affecting the fabrication quality of the silicon carbide epitaxial layer.

[0005] Applying relatively low process temperatures can effectively circumvent the above-mentioned defects. For example, using methyltrichlorosilane (MTS) as the reaction precursor gas can reduce the typical process temperature to approximately 1200 K–1600 K. However, in traditional chemical vapor deposition equipment, such as planetary deposition equipment, vertical deposition equipment, and horizontal deposition equipment, applying lower process temperatures can easily lead to low pyrolysis efficiency of methyltrichlorosilane (MTS), resulting in a decrease in the decomposition rate and utilization rate of the reaction precursor gas, which in turn affects the preparation efficiency of silicon carbide epitaxial layer crystals.

[0006] Furthermore, in the process of preparing large-size silicon carbide epitaxial layer crystals using traditional chemical vapor deposition equipment, it is difficult to avoid the temperature difference between the center and the edge of the silicon carbide substrate. This causes uneven distribution of the pyrolysis products of the precursor gas on the silicon carbide substrate, resulting in reduced uniformity of crystal growth, differences in defect density distribution, and thus affecting the preparation quality of silicon carbide epitaxial layer crystals. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing a silicon carbide chemical vapor deposition (CVD) equipment and method. This method reduces the process temperature to avoid high thermal stress while increasing the pyrolysis rate of the precursor gas, adjusting the uniformity of the temperature distribution in the horizontal direction above the silicon carbide substrate, and the uniformity of the distribution of the pyrolysis products of the precursor gas on the silicon carbide substrate. This improves the preparation efficiency and quality of silicon carbide epitaxial layer crystals.

[0008] This invention proposes a silicon carbide chemical vapor deposition reaction apparatus, including a flow guiding cavity and a crystal growth cavity. A base is provided in the central region of the crystal growth cavity, and a deposition platform for placing a silicon carbide substrate is formed on the base. The flow guiding cavity is provided with a first gas channel and a first heating element. The first gas channel extends in a bent shape, and the first heating element is evenly distributed on the inner wall of the first gas channel. The crystal growth cavity is provided with a second gas channel and a second heating element. The second gas channel is on the same vertical line as the central axis of the deposition platform, and the second heating element is evenly distributed on the inner wall of the second gas channel. The second gas channel is connected to the first gas channel. The first gas channel guides the incoming reaction gas to the second gas channel, and the second gas channel guides the reaction gas to the area above the deposition platform. The flow guiding cavities are two separate cavities located on both sides of the crystal growth cavity, and the tops of both flow guiding cavities are connected to the top of the crystal growth cavity.

[0009] Furthermore, the reaction apparatus also includes a top wall guide plate disposed on the top of the flow guiding cavity, and the top wall guide plate of the two flow guiding cavities is the same, so that the top wall guide plate forms the top wall of the two flow guiding cavities and the crystal growth cavity, and the first heating element includes a top wall guide plate heater built into the top wall guide plate.

[0010] Furthermore, the top wall guide plate heaters are multiple units that are equally spaced within the top wall guide plate, and the distance between two adjacent top wall guide plate heaters is no greater than 1 / 8 of the length of a single top wall guide plate heater.

[0011] Furthermore, the reaction device also includes a flow divider extending horizontally in the flow guiding cavity, with a gas passage provided on one side of the flow divider, thereby forming two first gas passages extending in a bent shape in the two flow guiding cavities respectively. The first heating element also includes a flow divider heater built into the flow divider.

[0012] Furthermore, the shunt heaters are multiple units that are equally spaced within the shunt, and the distance between two adjacent shunt heaters is no greater than 1 / 4 of the length of a single shunt heater.

[0013] Furthermore, the flow divider includes a first flow divider plate and a second flow divider plate, which are arranged sequentially from top to bottom in the flow guiding cavity. The gas passage includes a first channel located on one side of the first flow divider plate and a second channel located on the opposite side of the second flow divider plate, thereby forming two first gas passages extending in a bent shape in the two flow guiding cavities respectively. The flow divider heater includes a first flow divider plate heater built into the first flow divider plate and a second flow divider plate heater built into the second flow divider plate.

[0014] Furthermore, the reaction device also includes side wall guide plates disposed on both sides of the flow guiding cavity, and bottom wall guide plates disposed at the bottom of the flow guiding cavity. The distance between the top wall guide plate and the first flow dividing plate, the distance between the first flow dividing plate and the second flow dividing plate, and the distance between the second flow dividing plate and the bottom wall guide plate are all not greater than 1 / 4 of the distance between the two side wall guide plates.

[0015] Furthermore, the reaction apparatus also includes a heat insulation layer disposed outside the flow guiding cavity and the crystal growth cavity, and an outer cavity disposed outside the heat insulation layer.

[0016] Furthermore, the crystal growth cavity is also provided with a guide fluid, which is located above the base. The second gas channel is formed in the guide fluid, and the second heating element includes a guide fluid heater built into the guide fluid.

[0017] The present invention also provides a silicon carbide chemical vapor deposition reaction method, using the above-mentioned silicon carbide chemical vapor deposition reaction equipment, the method comprising the following steps: Step S1: Using the same gas introduction process, equal amounts of reaction precursor gas, reducing gas, and carrier gas are introduced into the flow guiding cavities on both sides of the crystal growth cavity. The reaction precursor gas is methyltrichlorosilane, the reducing gas is hydrogen, and the carrier gas is argon. Step S2: After the reaction precursor gas is uniformly decomposed in the flow guide cavity, its pyrolysis products are transferred to the crystal growth cavity and deposited on the silicon carbide substrate placed on the deposition platform. The tail gas after the reaction is then discharged from the crystal growth cavity.

[0018] The silicon carbide chemical vapor deposition reaction equipment and method proposed in this invention have the following beneficial effects: (1) The first gas channel of this device extends in a bent shape in the flow guide cavity, thereby prolonging the time for the reaction gas to flow through the first gas channel. The first heating element is evenly distributed on the inner wall of the first gas channel, thereby generating a uniform heat field in the first gas channel, increasing the pyrolysis rate of the reaction precursor gas, thereby increasing the preparation efficiency of silicon carbide epitaxial layer crystal, and improving the preparation quality of silicon carbide epitaxial layer crystal. (2) The equipment is provided with a second gas channel in the crystal growth cavity and a second heating element is distributed on the inner wall of the second gas channel. Through the joint heating of the base and the second heating element, a uniform thermal field is formed above the deposition platform, thereby adjusting the uniformity of the temperature distribution in the horizontal direction above the silicon carbide substrate and the uniformity of the distribution of the pyrolysis products of the reaction precursor gas on the silicon carbide substrate. This further consolidates the uniform pyrolysis effect of the reaction precursor gas, which is conducive to the uniform deposition of the pyrolysis products on the surface of the silicon carbide substrate, thereby improving the preparation efficiency of silicon carbide epitaxial layer crystal and improving the preparation quality of silicon carbide epitaxial layer crystal. (3) The flow guiding cavities of this equipment are two located on both sides of the crystal growth cavity, and the air inlets are two located on the side of the two flow guiding cavities away from the crystal growth cavity. The top of the two flow guiding cavities is connected to the top of the crystal growth cavity, which not only reduces the vertical height of this silicon carbide chemical vapor deposition reaction equipment, which is beneficial to saving vertical space, but also further improves the preparation efficiency of silicon carbide epitaxial layer crystals. (4) The device also includes a top wall guide plate, which forms the top wall of two guide cavities and the crystal growth cavity. The first heating element includes a top wall guide plate heater built into the top wall guide plate, thereby heating through the top wall guide plate heater to form a uniform heat field in the first gas channel of the two guide cavities and improve the pyrolysis rate of the reaction precursor gas. (5) The top wall guide plate heaters of this equipment are multiple heaters that are equally spaced in the top wall guide plate, and the distance between two adjacent top wall guide plate heaters is no more than 1 / 8 of the length of a single top wall guide plate heater. This allows the multiple top wall guide plate heaters built into the top wall guide plate to heat the reaction gas more evenly as the reaction gas flows from the guide cavities on both sides to the crystal growth cavity. (6) The device also includes a flow divider, which extends horizontally in the flow guide cavity and has an air passage on one side of the flow divider, thereby forming two first gas passages that extend in a bent shape in the two flow guide cavities respectively. The first heating element also includes a flow divider heater built into the flow divider, thereby heating together by the top wall flow guide plate heater built into the top wall flow guide plate and the flow divider heater built into the flow divider, forming a uniform heat field in the first gas passage and improving the pyrolysis rate of the reaction precursor gas. (7) The flow divider heaters of this equipment are multiple heaters that are equally spaced in the flow divider, and the distance between two adjacent flow divider heaters is no more than 1 / 4 of the length of a single flow divider heater. This allows the multiple flow divider heaters built into the flow divider to heat the reaction gas more evenly as the reaction gas flows from the guide cavities on both sides to the crystal growth cavity. (8) The flow divider of this equipment includes a first flow divider plate and a second flow divider plate. The first flow divider plate and the second flow divider plate are arranged from top to bottom in the flow guide cavity. The gas passage includes a first channel provided on one side of the first flow divider plate and a second channel provided on the opposite side of the second flow divider plate, thereby forming two first gas channels with multiple bends and extensions in the two flow guide cavities, further extending the time for the reaction gas to flow through the first gas channel. (9) The flow divider heater of this equipment includes a first flow divider heater built into the first flow divider plate and a second flow divider heater built into the second flow divider plate. Thus, by heating simultaneously through the top wall guide plate heater built into the top wall guide plate, the first flow divider heater built into the first flow divider plate, and the second flow divider heater built into the second flow divider plate, a uniform thermal field is formed in the first gas channel, thereby improving the pyrolysis rate of the reaction precursor gas. (10) The distance between the top wall guide plate and the first flow divider plate, the distance between the first flow divider plate and the second flow divider plate, and the distance between the second flow divider plate and the bottom wall guide plate are set to be no more than 1 / 4 of the distance between the side wall guide plates on the left and right sides of the flow guide cavity, thereby further improving the uniformity of temperature distribution in the flow guide cavity. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In these drawings, similar reference numerals are used to denote similar elements.

[0020] Figure 1 This is a schematic diagram of the structure of a silicon carbide chemical vapor deposition reaction apparatus according to a first embodiment of the present invention; Figure 2This is a fluid distribution cloud map of a silicon carbide chemical vapor deposition reaction apparatus according to an embodiment of the present invention; Figure 3 The decomposition rate of methyltrichlorosilane (MTS) from the center to the edge of the base at a position 0.5 mm above the base in Embodiment 1 of a silicon carbide chemical vapor deposition reaction apparatus of the present invention; Figure 4 The molar fraction of silicon-containing vapor phase material (SiCl2) at the center to the edge of the base, 0.5 mm above the base, in Embodiment 1 of a silicon carbide chemical vapor deposition reaction apparatus of the present invention; Figure 5 The molar fraction of carbon-containing gaseous material (C2H2) from the center of the base to the edge of the base, 0.5 mm above the base, in Embodiment 1 of a silicon carbide chemical vapor deposition reactor according to an embodiment of the present invention. Figure 6 This is a schematic diagram of a second embodiment of a silicon carbide chemical vapor deposition reaction apparatus according to an embodiment of the present invention.

[0021] In the diagram: 1. Flow guiding cavity; 11. Air inlet; 12. Top wall flow guide plate; 13. Side wall flow guide plate; 14. Bottom wall flow guide plate; 15. First flow divider plate; 16. Second flow divider plate; 17. Third flow divider plate; 2. Crystal growth cavity; 21. Air outlet; 22. Base; 23. Flow guide; 24. Support base; 3. First flow divider plate heater; 4. Second flow divider plate heater; 5. Third flow divider plate heater; 6. Top wall flow guide plate heater; 7. Flow guide heater; 8. Insulation layer; 9. Outer cavity. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] An embodiment of the present invention provides a silicon carbide chemical vapor deposition reaction apparatus, comprising a flow guiding cavity 1 and a crystal growth cavity 2. The flow guiding cavity 1 is provided with an air inlet 11, and the crystal growth cavity 2 is provided with an air outlet 21. The crystal growth cavity 2 is connected to the flow guiding cavity 1, thereby allowing the reaction gas to be introduced through the air inlet 11, so that the reaction gas flows through the flow guiding cavity 1 and then flows into the crystal growth cavity 2.

[0024] In this application, the reaction gas is a mixture of equal amounts of methyltrichlorosilane (MTS), hydrogen (H2), and argon (Ar), wherein methyltrichlorosilane (MTS) serves as the precursor gas, hydrogen (H2) serves as both the reaction gas and the reducing gas, and argon (Ar) serves as the carrier gas.

[0025] A base 22 is set in the central region of the crystal growth cavity 2. A deposition platform for placing a silicon carbide substrate is formed on the upper surface of the base 22. The reaction precursor gas in the reaction gas is thermally decomposed to form pyrolysis products. The pyrolysis products are deposited on the silicon carbide substrate on the deposition platform to form a silicon carbide epitaxial layer crystal. The crystal growth cavity 2 is provided with an outlet 21. The exhaust gas after the reaction is discharged from the crystal growth cavity 2 through the outlet 21, thereby completing the preparation of the silicon carbide epitaxial layer crystal.

[0026] In this application, the flow guiding cavity 1 is provided with a first gas channel and a first heating element. The first gas channel extends in a bent shape, and the first heating element is evenly distributed on the inner wall of the first gas channel. The first gas channel is connected to the gas inlet 11, so that the reaction gas flowing into the gas inlet 11 flows through the first gas channel and enters the crystal growth cavity 2.

[0027] In this process, because the first gas channel extends in a bent shape, the time for the reactant gas to flow through the first gas channel can be extended. Moreover, the first heating element is evenly distributed on the inner wall of the first gas channel. Thus, when the reactant gas flows through the first gas channel, the first heating element generates a uniform thermal field in the first gas channel, which uniformly heats the reactant gas. This causes the precursor gas in the reactant gas to form pyrolysis products after thermal decomposition, thereby increasing the pyrolysis rate of the precursor gas and improving the preparation efficiency and quality of silicon carbide epitaxial layer crystals.

[0028] A second gas channel and a second heating element are provided in the crystal growth cavity 2. The second gas channel is located above the base 22 and is on the same vertical line as the central axis of the deposition platform. The second heating element is evenly distributed on the inner wall of the second gas channel.

[0029] The second gas channel is connected to the first gas channel. After the reaction gas flows through the first gas channel, it flows to the second gas channel and then to the deposition platform, so that the pyrolysis products of the reaction precursor gas are deposited on the silicon carbide substrate on the deposition platform to form silicon carbide epitaxial layer crystals. The tail gas after the reaction is discharged from the outlet 21.

[0030] During this process, since the second gas channel is located above the base 22 and is on the same vertical line as the central axis of the deposition platform, the second heating element is evenly distributed on the inner wall of the second gas channel. In this application, a heating module is provided on the base 22, so that the base 22 has a heating function. Specifically, the heating method of the heating module can be induction heating or resistance heating.

[0031] Therefore, through the combined heating of the base 22 and the second heating element, a uniform thermal field is formed above the deposition platform, thereby adjusting the uniformity of the temperature distribution in the horizontal direction above the silicon carbide substrate and the uniformity of the distribution of the pyrolysis products of the reaction precursor gas on the silicon carbide substrate. This further consolidates the uniform pyrolysis effect of the reaction precursor gas, which is conducive to the uniform deposition of pyrolysis products on the surface of the silicon carbide substrate, thereby improving the preparation efficiency of silicon carbide epitaxial layer crystals and improving the preparation quality of silicon carbide epitaxial layer crystals.

[0032] Example 1, see Figure 1 : In this embodiment, two flow guiding cavities 1 and one crystal growth cavity 2 are provided. The two flow guiding cavities 1 are respectively provided on both sides of the crystal growth cavity 2, that is, one flow guiding cavity 1 is provided on each side of the crystal growth cavity 2. Each flow guiding cavity 1 is provided with an air inlet 11, which is located on the side of the flow guiding cavity 1 away from the crystal growth cavity 2. The tops of the two flow guiding cavities 1 are connected to the top of the crystal growth cavity 2.

[0033] External reaction gases flow into two guiding cavities 1 through two inlets 11. After passing through the first gas channel in the two guiding cavities 1, they flow from the top of the two guiding cavities 1 to the top of the crystal growth cavity 2. Then, under the guidance of the second gas channel in the crystal growth cavity 2, they flow towards the bottom of the crystal growth cavity 2, causing the pyrolysis products of the reaction precursor gases to be deposited on the silicon carbide substrate on the deposition platform to form silicon carbide epitaxial layer crystals. The exhaust gas after the reaction is discharged from the outlet 21 at the bottom of the crystal growth cavity 2.

[0034] Since the inlet 11 is located on the side of the flow guiding cavity 1 away from the crystal growth cavity 2, and the tops of both flow guiding cavities 1 are connected to the top of the crystal growth cavity 2, the reaction gas introduced from the inlet 11 on one side of the flow guiding cavity 1 first flows horizontally, then upwards, and finally flows horizontally from the top of the flow guiding cavity 1 to the top of the crystal growth cavity 2. This causes the first gas channel through which the reaction gas flows in the flow guiding cavity 1 to extend in a bent shape, prolonging the time for the reaction gas to flow through the first gas channel. Then, through the first heating element uniformly distributed on the inner wall of the first gas channel, a uniform thermal field is formed in the first gas channel, which uniformly heats the reaction gas flowing through the first gas channel, thereby improving the pyrolysis rate of the reaction precursor gas.

[0035] In this embodiment, two flow guide cavities 1 are respectively set on both sides of the crystal growth cavity, thereby compressing the vertical height of the silicon carbide chemical vapor deposition reaction equipment, which helps to save vertical space. At the same time, the reaction gas is introduced through the air inlet 11 on the two flow guide cavities 1, thereby further improving the preparation efficiency of silicon carbide epitaxial layer crystals.

[0036] Specifically, in this embodiment, the reaction apparatus further includes a top wall guide plate 12, a side wall guide plate 13, and a bottom wall guide plate 14. The side wall guide plate 13 and the bottom wall guide plate 14 respectively form the side wall and bottom wall of the flow guiding cavity 1. The top wall guide plate 12 of the two flow guiding cavities 1 is the same, so that the top wall guide plate 12 simultaneously forms the top wall of both flow guiding cavities 1 and the crystal growth cavity 2, thereby making the top of both flow guiding cavities 1 connected to the top of the crystal growth cavity 2.

[0037] Two air inlets 11 penetrate the sidewall guide plates 13 of the two flow guide cavities 1 in a horizontal direction, thereby forming two first gas channels extending in a bent shape between the sidewall guide plates 13, the bottom guide plate 14 and the top guide plate 12 of the two flow guide cavities 1; the first heating element includes a top guide plate heater 6 built into the top guide plate 12, thereby heating the first gas channels of the two flow guide cavities 1 to form a uniform thermal field and improve the pyrolysis rate of the reaction precursor gas.

[0038] Furthermore, in this embodiment, the reaction device also includes a flow divider, which extends horizontally between the top wall guide plate 12 and the bottom wall guide plate 14. That is, the flow divider is perpendicularly arranged with the two opposite side wall guide plates 13, and one end is connected to one side wall guide plate 13, while the other end is spaced a certain distance from the opposite side wall guide plate 13, thereby forming a gas passage for gas flow between the flow divider and the opposite side wall guide plate 13.

[0039] After the reactive gas flows in from one side of the flow guide cavity 1, it first flows horizontally under the guidance of the flow divider and the bottom wall guide plate 14, then flows upward through the gas passage between the flow divider and the side wall guide plate 13, and finally flows from the top of the flow guide cavity 1 to the top of the crystal growth cavity 2 under the guidance of the top wall guide plate 12. This causes the first gas passage through which the reactive gas flows in the flow guide cavity 1 to extend in a bent shape, thus prolonging the time for the reactive gas to flow through the first gas passage.

[0040] The first heating element also includes a flow divider heater, which is built into the flow divider. The flow divider heater is heated by the top wall guide plate heater 6 built into the top wall guide plate 12 and the flow divider heater built into the flow divider, forming a uniform thermal field in the first gas channel and improving the pyrolysis rate of the reaction precursor gas.

[0041] Specifically, in this embodiment, the flow divider includes a first flow divider plate 15 and a second flow divider plate 16. The first flow divider plate 15 and the second flow divider plate 16 are arranged from top to bottom between the top wall guide plate 12 and the bottom wall guide plate 14. One end of the first flow divider plate 15 and the second flow divider plate 16 are respectively connected to the opposite side wall guide plates 13, and the other end is spaced a certain distance from the opposite side wall guide plate 13. Thus, a first channel is formed on one side of the first flow divider plate 15, and a second channel is formed on the opposite side of the second flow divider plate 16. This forms two first gas channels with multiple bends and extensions in the two flow guide cavities 1, further extending the time for the reaction gas to flow through the first gas channels.

[0042] The flow divider heater includes a first flow divider heater 3 built into the first flow divider 15 and a second flow divider heater 4 built into the second flow divider 16. Thus, the top wall guide plate heater 6 built into the top wall guide plate 12, the first flow divider heater 3 built into the first flow divider 15, and the second flow divider heater 4 built into the second flow divider 16 heat the gas simultaneously, forming a uniform thermal field in the first gas channel and improving the pyrolysis rate of the reaction precursor gas.

[0043] Specifically, in actual implementation, the first flow divider heater 3, the second flow divider heater 4, and the top wall guide plate heater 6 can be resistance heating elements respectively built into the first flow divider 15, the second flow divider 16, and the top wall guide plate 12.

[0044] Traditional vertical deposition equipment typically places heaters uniformly on the inner sidewall of the reactor. In this embodiment, the first heating element includes a top wall guide plate heater 6 built into the top wall guide plate 12, a first flow divider heater 3 built into the first flow divider plate 15, and a second flow divider heater 4 built into the second flow divider plate 16. The distance between the top wall guide plate 12 and the first flow divider plate 15, the distance between the first flow divider plate 15 and the second flow divider plate 16, and the distance between the second flow divider plate 16 and the bottom wall guide plate 14 are much smaller than the distance between the side wall guide plates 13 on the left and right sides of the flow guide cavity 1. This improves the uniformity of temperature distribution in the flow guide cavity 1, thereby increasing the pyrolysis rate of the precursor gas.

[0045] Preferably, in this embodiment, the distance between the top wall guide plate 12 and the first diverter plate 15, the distance between the first diverter plate 15 and the second diverter plate 16, and the distance between the second diverter plate 16 and the bottom wall guide plate 14 are set to be no greater than 1 / 4 of the distance between the side wall guide plates 13 on the left and right sides of the guide cavity 1, thereby further improving the uniformity of temperature distribution in the guide cavity 1.

[0046] Specifically, in actual implementation, the distance L1 between the top wall guide plate 12 and the first diverter plate 15, the distance L2 between the first diverter plate 15 and the second diverter plate 16, the distance L3 between the second diverter plate 16 and the bottom wall guide plate 14, and the distance L4 between the left and right side wall guide plates 13 can have the following relationship: L1=L2=L3; L1=3 / 16L4, thereby further improving the uniformity of temperature distribution in the guide cavity 1.

[0047] In this application, after the reactive gas flows into the flow guiding cavity 1 from the inlet 11, it first moves horizontally under the guidance of the second flow divider 16 and the bottom wall flow guide 14, then flows upward through the channel between the second flow divider 16 and the side wall flow guide 13, then moves horizontally under the guidance of the first flow divider 15 and the second flow divider 16, then flows upward through the channel between the first flow divider 15 and the side wall flow guide 13, and finally flows to the crystal growth cavity 2 under the guidance of the first flow divider 15 and the top wall flow guide 12.

[0048] Therefore, in this embodiment, the first flow divider heater 3 built into the first flow divider 15, the second flow divider heater 4 built into the second flow divider 16, and the top wall guide plate heater 6 built into the top wall guide plate 12 are all arranged at equal intervals, so that during the process of the reaction gas flowing from the guide cavities 1 on both sides to the crystal growth cavity 2, the multiple second flow divider heaters 4 and the multiple top wall guide plate heaters 6 can better heat the reaction gas.

[0049] Furthermore, in this embodiment, the distance between two adjacent first diverter heaters 3 is no greater than 1 / 4 of the length of a single first diverter heater 3; the distance between two adjacent second diverter heaters 4 is no greater than 1 / 4 of the length of a single second diverter heater 4.

[0050] The distance between two adjacent top wall guide plate heaters 6 is no greater than 1 / 8 of the length of a single top wall guide plate heater 6. This allows the multiple first flow divider heaters 3 built into the first flow divider 15, the multiple second flow divider heaters 4 built into the second flow divider 16, and the multiple top wall guide plate heaters 6 built into the top wall guide plate 12 to heat the reaction gas more uniformly as the reaction gas flows from the guide cavities 1 on both sides to the crystal growth cavity 2.

[0051] Furthermore, in this embodiment, the plurality of first flow divider heaters 3 built into the first flow divider 15 are staggered with the plurality of second flow divider heaters 4 built into the second flow divider 16, so that when the reaction gas flows through the region between the second flow divider 16 and the first flow divider 15, the plurality of first flow divider heaters 3 and the plurality of second flow divider heaters 4 can better heat the reaction gas.

[0052] In this embodiment, the reaction device further includes a heat insulation layer 8 and an outer cavity 9, wherein the heat insulation layer 8 is disposed outside the flow guiding cavity 1 and the crystal growth cavity 2, and the outer cavity 9 is disposed outside the heat insulation layer 8.

[0053] Sidewall guide plates 13 and bottom wall guide plates 14 are disposed on the inner side of the heat insulation layer 8 to form the sidewall and bottom wall of the flow guiding cavity 1; top wall guide plates 12 are disposed on the inner side of the heat insulation layer 8 to form the top wall of the two flow guiding cavities 1 and the crystal growth cavity 2; the heat insulation layer 8 forms the sidewall and bottom wall of the crystal growth cavity 2, thereby forming a closed structure of the flow guiding cavity 1 and the crystal growth cavity 2.

[0054] The inlet 11 horizontally penetrates the outer cavity 9, the heat insulation layer 8, and the side wall guide plate 13, thereby connecting the guide cavity 1 with the outside world, allowing the reaction gas from the outside to flow into the guide cavity 1 through the inlet 11. The outlet 21 vertically penetrates the outer cavity 9 and the heat insulation layer 8, thereby connecting the crystal growth cavity 2 with the outside world, allowing the exhaust gas from the reaction in the crystal growth cavity 2 to be discharged through the outlet 21.

[0055] A heat insulation layer 8 is disposed outside the flow guiding cavity 1 and the crystal growth cavity 2 to reduce heat loss from the flow guiding cavity 1 and the crystal growth cavity 2, thereby further improving the pyrolysis rate of the reaction precursor gas; an outer cavity 9 is disposed outside the heat insulation layer 8 to provide solid support for the heat insulation layer 8. Specifically, in this application, the outer cavity 9 may be a quartz layer surrounding the heat insulation layer 8 and the crystal growth heat insulation layer 8.

[0056] In this embodiment, the crystal growth cavity 2 is also provided with a fluid guide 23 and a support 24. The support 24 extends vertically on the heat insulation layer 8, and the base 22 is disposed on the top of the support 24, thereby supporting the base 22 through the support 24.

[0057] The guide fluid 23 is positioned above the base 22 and at the junction of the guide cavity 1 and the crystal growth cavity 2. A second gas channel is formed in the guide fluid 23, which connects the second gas channel with the first gas channel. This allows the gas flowing through the first gas channel to flow into the second gas channel and, under the guidance of the second gas channel, to flow into the deposition platform of the base 22.

[0058] The second heating element includes a fluid-conducting heater 7 built into the fluid-conducting fluid 23. Through the combined heating of the base 22 and the fluid-conducting heater 7, a uniform thermal field is formed above the deposition platform. This regulates the uniformity of the temperature distribution in the horizontal direction above the silicon carbide substrate and the uniformity of the pyrolysis products of the precursor gas on the silicon carbide substrate. This further consolidates the uniform pyrolysis effect of the precursor gas, facilitating the uniform deposition of pyrolysis products on the surface of the silicon carbide substrate, thereby improving the preparation efficiency and quality of the silicon carbide epitaxial layer crystal. Specifically, in practical implementation, the fluid-conducting heater 7 can be a resistance heating element built into the fluid-conducting fluid 23.

[0059] Since the reactive gas flows from the top of the guide cavity 1 on both sides to the top of the crystal growth cavity 2, it flows through the second gas channel under the guidance of the top wall guide plate 12 and the guide fluid 23. At this time, the reactive gas will immediately flow through the second gas channel to the deposition platform of the base 22 and be deposited on the silicon carbide substrate on the deposition platform. Therefore, in this embodiment, the guide fluid heater 7 built into the guide fluid 23 is completely distributed on the upper surface of the guide fluid 23, thereby further enhancing the heating effect of the guide fluid heater 7 on the reactive gas.

[0060] This embodiment also provides a method for product deposition using a silicon carbide chemical vapor deposition reaction apparatus provided in Embodiment 1, and its simulation.

[0061] The method includes the following steps: Step S1: At the gas inlet 11 of the flow guiding cavity 1 located on both sides of the crystal growth cavity 2, the same gas introduction process is adopted to introduce equal amounts of reaction precursor gas, reducing gas, and carrier gas into the gas inlet 11 on both sides; the introduced gases are methyltrichlorosilane (MTS), hydrogen (H2), and argon (Ar), where methyltrichlorosilane (MTS) is used as the reaction precursor gas, hydrogen (H2) is used as the reaction gas and reducing gas, and argon (Ar) is used as the carrier gas.

[0062] Step S2: After the precursor gas is uniformly decomposed in the flow guide cavity 1, its pyrolysis products are transferred to the crystal growth cavity 2 and deposited on the silicon carbide substrate placed on the base 22. The tail gas after the reaction is then discharged from the outlet 21.

[0063] In this application, methyltrichlorosilane (MTS) is used as the reaction precursor gas, hydrogen (H2) as the reaction gas and reducing gas, and argon (Ar) as the carrier gas. An equal amount of a mixture of methyltrichlorosilane (MTS), hydrogen (H2) and argon (Ar) is introduced into the flow guide cavity 1, thereby reducing the process temperature for preparing silicon carbide epitaxial layer crystals by chemical vapor deposition to about 1200K, thus reducing the process temperature and avoiding high thermal stress.

[0064] Furthermore, by uniformly decomposing the precursor gas in the flow channel 1, the pyrolysis rate of the precursor gas and the uniformity of the distribution of the pyrolysis products of the precursor gas on the silicon carbide substrate are improved, thereby enhancing the preparation efficiency and quality of the silicon carbide epitaxial layer crystal.

[0065] The main process parameters used in the simulation are: (1) Argon (Ar) accounts for 95% of the inlet gas; (2) The ratio of methyltrichlorosilane (MTS) to hydrogen (H2) is 1:1; (3) The airflow velocity at the air inlet 11 of the two side guide chambers 1 is the same, the average inlet velocity is 0.42 m / s, and the gas pressure is 100 mbar. (4) The set temperatures of the top wall guide plate heater 6, the first flow divider heater 3, the second flow divider heater 4, and the base 22 heating module are the same, namely 1000 K, 1200 K and 1400 K respectively.

[0066] The fluid distribution cloud map in the silicon carbide chemical vapor deposition reactor of Example 1, obtained through flow field simulation, is shown below. Figure 2 As shown, gas enters the flow guide cavity 1 through the gas inlet 11, flows through the flow guide cavity 1 to the crystal growth cavity 2, flows to the base 22, and then flows from the center of the base 22 to the edge. After that, the gas flows out through the gas outlet 21.

[0067] As an example, attached Figure 3 The diagram shows the consumption rate of methyltrichlorosilane (MTS) at a distance of 0.5 mm above the base 22 of a silicon carbide chemical vapor deposition reactor provided in Example 1, from the center of the base 22 to the edge of the base 22. At 1000 K, the consumption rate of methyltrichlorosilane (MTS) above the base 22 is approximately 50%, at 1200 K the consumption rate of methyltrichlorosilane (MTS) above the base 22 is slightly higher than 55%, and at 1400 K the consumption rate of MTS above the base 22 is approximately 100%.

[0068] As can be seen from the application example 1, the silicon carbide chemical vapor deposition reaction apparatus can achieve a high reaction precursor consumption rate above the base 22 because the gas path of the guide cavity 1 effectively extends the residence time of the reaction gas in the guide cavity 1. It can also achieve a methyltrichlorosilane (MTS) decomposition rate of about 50% at relatively low temperatures (1200 K and 1000 K).

[0069] Since the consumption rate of methyltrichlorosilane (MTS) at a specific temperature is mainly related to the residence time of methyltrichlorosilane (MTS) in the high-temperature reaction zone, it can be reasonably inferred that in a conventional reactor that does not have the gas path and heater distribution of the flow channel 1 in Embodiment 1 of the present invention, the corresponding residence time of the gas from the inlet 11 to the base 22 is significantly less than that of the corresponding residence time of the gas from the inlet 11 to the base 22 in Embodiment 1 of the present invention. Therefore, the consumption rate of methyltrichlorosilane (MTS) above the base 22 should be significantly lower than that of the methyltrichlorosilane (MTS) above the base 22 of the silicon carbide chemical vapor deposition reactor provided in Embodiment 1 of the present invention.

[0070] As an example, attached Figure 4 and attached Figure 5 The diagram shows the typical content of silicon-containing gaseous material (SiCl2) and typical carbon-containing gaseous material (C2H2) from the center of the base 22 to the edge of the base 22, 0.5 mm above the base of the silicon carbide chemical vapor deposition reaction apparatus provided in Example 1.

[0071] When the heater temperature is uniformly set to 1000 K, 1200 K and 1400 K respectively, the material distribution above the surface of the base 22 shows good uniformity, indicating that the silicon carbide chemical vapor deposition reaction equipment provided in Example 1 can provide a uniform material distribution atmosphere for the crystal growth space while improving the decomposition rate of the reaction precursor, which is beneficial to improving the crystal growth efficiency and crystal growth quality.

[0072] Furthermore, the molar fractions of silicon-containing gaseous material (SiCl2) and carbon-containing gaseous material (C2H2) at different temperatures showed significant differences, indicating that the silicon carbide chemical vapor deposition reaction equipment provided in Example 1 can precisely adjust the content of the material above the substrate 22 through temperature control, thereby implementing precise control of crystal growth.

[0073] Example 2, see Figure 6 : In this application, the flow guiding cavity 1 and the crystal growth cavity 2 are arranged sequentially in a vertical direction, that is, the flow guiding cavity 1 is located directly above the crystal growth cavity 2, and the central axis of the flow guiding cavity 1 and the central axis of the crystal growth cavity 2 are on the same vertical line. The gas inlet 11 is located at the top of the flow guiding cavity 1, and the top of the first gas channel is connected to the gas inlet 11, so that the reaction gas flowing into the gas inlet 11 flows into the first gas channel.

[0074] Since the first gas channel extends in a bent shape in the flow guide cavity 1, and the first heating element is evenly distributed on the inner wall of the first gas channel, a uniform thermal field is formed in the first gas channel, and the time for the reaction gas to flow through the first gas channel is extended, thereby increasing the pyrolysis rate of the reaction precursor gas.

[0075] The bottom of the flow guiding cavity 1 is connected to the top of the crystal growth cavity 2, that is, the bottom of the first gas channel is connected to the top of the second gas channel. The gas outlet 21 is located on the side of the crystal growth cavity 2, so that the gas flowing through the first gas channel flows to the second gas channel, and then flows through the second gas channel to the deposition platform.

[0076] During this process, the pyrolysis products of the reaction precursor gas are deposited on the silicon carbide substrate on the deposition platform to form a silicon carbide epitaxial layer crystal, and the exhaust gas after the reaction is discharged from the gas outlet 21 on the side of the crystal growth cavity 2. In this application, the gas outlet 21 can be two outlets respectively provided on both sides of the crystal growth cavity 2.

[0077] Since the second gas channel is located above the base 22 and is on the same vertical line as the central axis of the deposition platform, after the gas flows through the second gas channel, it diffuses from the center of the deposition platform to both sides above the deposition platform, so that the pyrolysis products of the reaction precursor gas are evenly distributed on the silicon carbide substrate, which is beneficial to the uniform growth of large-size silicon carbide substrates. The tail gas after the reaction flows out from the gas outlets 21 on both sides of the crystal growth cavity 2.

[0078] Specifically, in this embodiment, the reaction apparatus further includes a top wall guide plate 12, a side wall guide plate 13, a bottom wall guide plate 14, and a flow divider. The top wall guide plate 12 and the side wall guide plate 13 form the top wall and side wall of the flow guiding cavity 1, respectively. The bottom wall guide plate 14 forms the bottom wall of the flow guiding cavity 1 and the top wall of the crystal growth cavity 2. The flow divider is disposed between the top wall guide plate 12 and the side wall guide plate 13, thereby forming a first gas channel extending in a bent shape in the flow guiding cavity 1.

[0079] The air inlet 11 penetrates the top wall guide plate 12, thereby connecting the top of the first gas channel with the outside, allowing the external reaction gas to enter the first gas channel through the air inlet 11. A connecting port is provided on the bottom wall guide plate 14, through which the second gas channel connects with the first gas channel, thereby connecting the bottom of the guide cavity 1 with the top of the crystal growth cavity 2.

[0080] The first heating element is built into the flow divider, thereby creating a uniform thermal field within the first gas channel. This allows the reactant gas to be uniformly heated as it flows through the first gas channel, causing the precursor gases in the reactant gas to undergo thermal decomposition to form pyrolysis products. The gas that has undergone the pyrolysis reaction in the first gas channel then flows through the connecting port to the second gas channel.

[0081] Specifically, in this application, there are two implementation methods for the flow divider. The first implementation method is as follows: the flow divider includes a first flow divider plate 15, which extends horizontally between the top wall guide plate 12 and the bottom wall guide plate 14, and is connected to the side wall guide plate 13 at both ends. Thus, the flow guide cavity 1 is divided into a first layer space and a second layer space distributed from top to bottom through the first flow divider plate 15.

[0082] When the air inlet 11 penetrates the top wall guide plate 12, it connects the first layer space with the outside. A first channel is provided on the first diversion plate 15, which connects the first layer space with the second layer space, thereby forming a first gas channel in the guide cavity 1, so that the reaction gas flows into the first layer space through the air inlet 11 and then flows into the second layer space through the first channel.

[0083] The connecting port set on the bottom wall guide plate 14 connects the second layer space with the second gas channel, thereby connecting the first gas channel with the second gas channel, so that the gas in the second layer space after the pyrolysis reaction flows to the second gas channel.

[0084] In this application, the central axes of the air inlet 11 and the connecting port are on the same vertical line, while the central axis of the first channel is not on the same vertical line as the central axes of the air inlet 11 and the connecting port. This causes the first gas channel formed in the flow guide cavity 1 to extend in a bent shape, thus prolonging the time for the reaction gas to flow through the first gas channel.

[0085] The first heating element includes a first flow divider heater 3, which is built into the first flow divider 15. The first flow divider heater 3 heats the gas and forms a uniform thermal field in the first and second layers of space, thereby uniformly heating the reaction gas flowing through the first and second layers of space and improving the pyrolysis rate of the reaction precursor gas.

[0086] In this application, since the top wall guide plate 12 and the bottom wall guide plate 14 are arranged parallel to each other in the vertical direction, the air inlet 11 can be set at the center of the top wall guide plate 12 and the connecting port can be set at the center of the bottom wall guide plate 14, so that the central axis of the air inlet 11 and the connecting port are on the same vertical line.

[0087] Since the central axes of the flow guiding cavity 1 and the crystal growth cavity 2 are on the same vertical line, the base 22 is set in the central region of the crystal growth cavity 2, and the central axis of the second air inlet channel and the deposition platform formed on the base 22 are on the same vertical line, the air inlet 11, the connecting port, the second air inlet channel and the central axis of the deposition platform are all on the same vertical line.

[0088] In this application, since the top wall guide plate 12, the first diverter plate 15 and the bottom wall guide plate 14 are arranged parallel to each other in the vertical direction, the first channel can be set at the eccentric position of the first diverter plate 15, so that the first channel is not on the same vertical line as the central axis of the air inlet 11 and the connecting port, thereby making the first gas channel formed in the guide cavity 1 extend in a bent shape.

[0089] Furthermore, in this embodiment, the first channel can be configured as two channels distributed on both sides of the central axis of the first diverter plate 15, so that the reactant gas flowing into the first layer space flows to both sides and flows into the second layer space from the two first channels respectively.

[0090] The reacting gases entering the second space converge towards the center and flow into the second gas channel through the connecting opening. This prolongs the time the reacting gases spend flowing through the first gas channel and allows the uniform thermal field formed within the first gas channel to better heat the reacting gases. It is foreseeable that the two first channels, respectively located on both sides of the central axis of the first diverter plate 15, should be as close as possible to the edges of both ends of the first diverter plate 15.

[0091] The second implementation is as follows: the flow divider includes a first flow divider 15, a second flow divider 16 and a third flow divider 17. The first flow divider 15, the second flow divider 16 and the third flow divider 17 are arranged from top to bottom between the top wall guide plate 12 and the bottom wall guide plate 14, and both ends are connected to the side wall guide plate 13, dividing the flow guide cavity 1 into a first layer space, a second layer space, a third layer space and a fourth layer space distributed from top to bottom.

[0092] When the air inlet 11 penetrates the top wall guide plate 12, it connects the first layer of space with the outside; a first channel is provided on the first split plate 15, which connects the first layer of space with the second layer of space; a second channel is provided on the second split plate 16, which connects the second layer of space with the third layer of space. A third channel is provided on the third diversion plate 17, which connects the third layer space and the fourth layer space, thereby forming a first gas channel in the flow guide cavity 1, so that the reaction gas flows into the first layer space through the air inlet 11, then flows into the second layer space through the first channel, then flows into the third layer space through the second channel, and finally flows into the fourth layer space through the third channel.

[0093] The connecting port set on the bottom wall guide plate 14 connects the fourth layer space with the second gas channel, thereby connecting the first gas channel with the second gas channel, so that the gas in the fourth layer space after the pyrolysis reaction flows to the second gas channel.

[0094] In this application, the central axes of the air inlet 11, the second channel, and the connecting port are on the same vertical line, the central axes of the first channel and the third channel are on the same vertical line, and the central axes of the first channel and the third channel are not on the same vertical line as the central axes of the air inlet 11, the second channel, and the connecting port, thereby causing the first gas channel formed in the flow guide cavity 1 to extend in a bent shape, prolonging the time for the reaction gas to flow through the first gas channel.

[0095] The first heating element includes a first flow divider heater 3, a second flow divider heater 4, and a third flow divider heater 5. The first flow divider heater 3 is built into the first flow divider 15, the second flow divider heater 4 is built into the second flow divider 16, and the third flow divider heater 5 is built into the third flow divider 17. Thus, heating is achieved through the first flow divider heater 3, the second flow divider heater 4, and the third flow divider heater 5, forming a uniform thermal field in the first gas channel. This uniformly heats the reaction gas flowing through the first gas channel, thereby increasing the pyrolysis rate of the reaction precursor gas.

[0096] Specifically, in actual implementation, the first flow divider heater 3, the second flow divider heater 4, and the third flow divider heater 5 can be resistance heating elements respectively built into the first flow divider 15, the second flow divider 16, and the third flow divider 17.

[0097] In this application, since the top wall guide plate 12, the first diverter plate 15, the second diverter plate 16, the third diverter plate 17 and the bottom wall guide plate 14 are arranged in parallel intervals in the vertical direction, the air inlet 11 can be set at the center of the top wall guide plate 12, the second channel can be set at the center of the second diverter plate 16, and the connecting port can be set at the center of the bottom wall guide plate 14, so that the central axes of the air inlet 11, the second channel and the connecting port are on the same vertical line.

[0098] The first channel can be set at the eccentric position of the first diverter plate 15, and the third channel can be set at the eccentric position of the third diverter plate 17, so that the central axis of the first channel and the third channel are on the same vertical line, and the central axis of the first channel and the third channel are not on the same vertical line as the central axis of the air inlet 11, the second channel and the connecting port, so that the first gas channel formed in the flow guide cavity 1 extends in a bent shape.

[0099] Furthermore, in this embodiment, the first channel can be configured as two channels distributed on both sides of the central axis of the first diverter plate 15, so that the reaction gas flowing into the first layer space flows to both sides and flows into the second layer space from the two first channels respectively. The reaction gas entering the second layer space then gathers in the middle and flows into the third layer space from the second channel.

[0100] The third channel can be set as two distributed on both sides of the central axis of the third flow plate 17, so that the reaction gas flowing into the third layer space flows to both sides and flows into the fourth layer space from the two third channels respectively. The reaction gas entering the fourth layer space then gathers in the middle and flows into the second gas channel from the connecting port, thereby further prolonging the time of the reaction gas flowing through the first gas channel and making the uniform heat field formed in the first gas channel better heat the reaction gas.

[0101] It is foreseeable that the two first channels set on both sides of the central axis of the first diverter plate 15 should be as close as possible to the edges of both ends of the first diverter plate 15; the two third channels set on both sides of the central axis of the third diverter plate 17 should be as close as possible to the edges of both ends of the third diverter plate 17, and the two first channels set on both sides of the central axis of the first diverter plate 15 should be on the same vertical line as the central axis of the two third channels set on both sides of the central axis of the third diverter plate 17.

[0102] Since the first channel consists of two channels respectively located on both sides of the central axis of the first diverter plate 15, the reactant gas flowing into the first layer space flows to both sides. Therefore, in this application, a guide tip can be provided on the top of the first diverter plate 15, so that the guide tip extends towards the air inlet 11, and the central axis of the guide tip is on the same vertical line as the central axis of the air inlet 11, so that the gas flowing into the air inlet 11 flows better to both sides of the first layer space under the guidance of the guide tip.

[0103] Since the two first channels are arranged on both sides of the central axis of the first diverter plate 15, close to the edges of both ends of the first diverter plate 15, and the second channel is arranged at the center of the second diverter plate 16, in this application, the cross-sectional area of ​​the second diverter plate heater 4 built into the second diverter plate 16 is set to be larger than the cross-sectional area of ​​the first diverter plate heater 3 built into the first diverter plate 15, and the projection of the second diverter plate heater 4 above covers part of the first channel, so that the reaction gas flows through the first channel to the second layer space, and during the process of gathering towards the center in the second layer space, the second diverter plate heater 4 can heat the reaction gas to a greater extent.

[0104] Similarly, since the two third channels are arranged on both sides of the central axis of the third flow divider 17, and the second channel is located at the center of the second flow divider 16, in this application, the projection of the second flow divider heater 4 below covers part of the third channel, so that the reaction gas flows through the second channel to the third layer space, and during the process of flowing to both sides in the third layer space, the second flow divider heater 4 can heat the reaction gas to a greater extent.

[0105] In this application, after the reactant gas flows from the second channel at the center of the second diversion plate 16 to the third layer space, it flows to both sides in the third layer space. Therefore, in this application, the third diversion plate heater 5 built into the third diversion plate 17 can be a plurality of units equidistantly arranged from the center of the third diversion plate 17 to both sides. Thus, during the process of the reactant gas flowing through the second channel to the third layer space and flowing to both sides in the third layer space, and during the process of flowing through the third channel to the fourth layer space and converging towards the center in the fourth layer space, the third diversion plate heater 5 can heat the reactant gas to a greater extent.

[0106] Traditional vertical deposition equipment typically places heaters evenly on the inner sidewall of the reactor. However, in this embodiment, the first heating element includes a first split plate heater 3 built into the first split plate 15, a second split plate heater 4 built into the second split plate 16, and a third split plate heater 5 built into the third split plate 17. The distance between two adjacent split plates is much smaller than the distance between the sidewall guide plates 13 on the left and right sides of the guide cavity 1, thereby improving the uniformity of temperature distribution in the guide cavity 1 and thus increasing the pyrolysis rate of the precursor gas.

[0107] Preferably, in this embodiment, the spacing between two adjacent flow dividers is set to be no greater than 1 / 4 of the spacing between the flow dividers 13 on the left and right sides of the flow guide cavity 1, thereby further improving the uniformity of temperature distribution in the flow guide cavity 1.

[0108] Specifically, in actual implementation, the distance L1 between the top wall guide plate 12 and the first diverter plate 15, the distance L2 between the first diverter plate 15 and the second diverter plate 16, the distance L3 between the second diverter plate 16 and the third diverter plate 17, the distance L4 between the third diverter plate 17 and the bottom wall guide plate 14, and the distance L5 between the left and right side wall guide plates 13 can have the following relationship: L1=L2=L3=L4; L5=8L1, thereby further improving the uniformity of temperature distribution in the guide cavity 1.

[0109] Furthermore, in this embodiment, the silicon carbide chemical vapor deposition reaction apparatus also includes a heat insulation layer 8 and an outer cavity 9. The heat insulation layer 8 is disposed on the outside of the flow guiding cavity 1 and the crystal growth cavity 2 to slow down the heat loss in the flow guiding cavity 1 and the crystal growth cavity 2, thereby further improving the pyrolysis rate of the reaction precursor gas.

[0110] The outer cavity 9 is disposed on the outside of the heat insulation layer 8 to provide solid support for the heat insulation layer 8, the flow guiding cavity 1, and the crystal growth cavity 2. In this application, the outer cavity 9 may be a quartz layer surrounding the outside of the heat insulation layer 8, thereby providing solid support for the heat insulation layer 8, the flow guiding cavity 1, and the crystal growth cavity 2 through the quartz layer.

[0111] Specifically, the heat insulation layer 8 surrounds the interior of the heat insulation layer 8, and the top wall guide plate 12 and the side wall guide plate 13 are disposed inside the heat insulation layer 8 to form the top wall and side wall of the flow guiding cavity 1. The bottom wall guide plate 14 is disposed in the heat insulation layer 8 to form the bottom wall of the flow guiding cavity 1 and the top wall of the crystal growth cavity 2, thereby dividing the internal space of the heat insulation layer 8 into the flow guiding cavity 1 and the crystal growth cavity 2. The side wall and bottom wall of the crystal growth cavity 2 are formed by the heat insulation layer 8.

[0112] In this application, the air inlet 11 passes through the outer cavity 9, the heat insulation layer 8, and the top wall guide plate 12 in a vertical direction, thereby connecting the guide cavity 1 with the outside world, so that the reaction gas from the outside world can enter the guide cavity 1 in a vertical direction through the air inlet 11; the air outlet 21 passes through the outer cavity 9 and the heat insulation layer 8 in a horizontal direction, thereby connecting the crystal growth cavity 2 with the outside world, so that the exhaust gas after the reaction can be discharged from the crystal growth cavity 2 in a horizontal direction through the air outlet 21.

[0113] In this embodiment, the crystal growth cavity 2 is also provided with a fluid guide 23 and a support 24. The support 24 extends vertically on the heat insulation layer 8, and the base 22 is disposed on the top of the support 24, thereby supporting the base 22 through the support 24.

[0114] The guide fluid 23 is positioned above the base 22 and at the junction of the bottom of the guide cavity 1 and the top of the crystal growth cavity 2. A second gas channel is formed in the guide fluid 23, which connects the second gas channel with the first gas channel. This allows the gas flowing through the first gas channel to flow into the second gas channel and, under the guidance of the second gas channel, to flow into the deposition platform of the base 22.

[0115] The second heating element includes a fluid-conducting heater 7 built into the fluid-conducting fluid 23. Through the combined heating of the base 22 and the fluid-conducting heater 7, a uniform thermal field is formed above the deposition platform. This regulates the uniformity of the temperature distribution in the horizontal direction above the silicon carbide substrate and the uniformity of the pyrolysis products of the precursor gas on the silicon carbide substrate. This further consolidates the uniform pyrolysis effect of the precursor gas, facilitating the uniform deposition of pyrolysis products on the surface of the silicon carbide substrate, thereby improving the preparation efficiency and quality of the silicon carbide epitaxial layer crystal. Specifically, in practical implementation, the fluid-conducting heater 7 can be a resistance heating element built into the fluid-conducting fluid 23.

[0116] This embodiment also provides a method for product deposition using a silicon carbide chemical vapor deposition reactor provided in Embodiment 2, including the following steps: Step S1: Equal amounts of reaction precursor gas, reducing gas, and carrier gas are introduced into the flow chamber 1 through the air inlet 11; the introduced gases are methyltrichlorosilane (MTS), hydrogen (H2), and argon (Ar), respectively, wherein methyltrichlorosilane (MTS) is used as the reaction precursor gas, hydrogen (H2) is used as the reaction gas and reducing gas, and argon (Ar) is used as the carrier gas.

[0117] Step S2: After the precursor gas is uniformly decomposed in the flow guide cavity 1, its pyrolysis products are transferred to the crystal growth cavity 2 and deposited on the silicon carbide substrate placed on the base 22. The tail gas after the reaction is then discharged from the outlet 21.

[0118] In this application, methyltrichlorosilane (MTS) is used as the reaction precursor gas, hydrogen (H2) as the reaction gas and reducing gas, and argon (Ar) as the carrier gas. An equal amount of a mixture of methyltrichlorosilane (MTS), hydrogen (H2) and argon (Ar) is introduced into the flow guide cavity 1, thereby reducing the process temperature for preparing silicon carbide epitaxial layer crystals by chemical vapor deposition to about 1200K, thus reducing the process temperature and avoiding high thermal stress.

[0119] Furthermore, by uniformly decomposing the precursor gas in the flow channel 1, the pyrolysis rate of the precursor gas and the uniformity of the distribution of the pyrolysis products of the precursor gas on the silicon carbide substrate are improved, thereby enhancing the preparation efficiency and quality of the silicon carbide epitaxial layer crystal.

[0120] The above-described contents can be implemented individually or in various combinations, and these variations are all within the protection scope of this invention.

[0121] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silicon carbide chemical vapor deposition reaction apparatus, characterized in that: It includes a flow channel cavity (1) and a crystal growth cavity (2), wherein a base (22) is provided in the central region of the crystal growth cavity (2), and a deposition platform for placing a silicon carbide substrate is formed on the base (22); The flow guide cavity (1) is provided with a first gas channel and a first heating element. The first gas channel extends in a bent shape, and the first heating element is evenly distributed on the inner wall of the first gas channel. The crystal growth cavity (2) is provided with a second gas channel and a second heating element. The second gas channel is on the same vertical line as the central axis of the deposition platform, and the second heating element is evenly distributed on the inner wall of the second gas channel. The second gas channel is connected to the first gas channel. The first gas channel guides the reaction gas entering from the outside to the second gas channel. The second gas channel guides the reaction gas to the area above the deposition platform. The reaction gas is a mixture of equal amounts of methyltrichlorosilane, hydrogen and argon. Methyltrichlorosilane is used as a reaction precursor gas, hydrogen is used as a reaction gas and a reducing gas, and argon is used as a carrier gas. The flow guiding cavity (1) consists of two separate cavities located on both sides of the crystal growth cavity (2), and the tops of both flow guiding cavities (1) are connected to the top of the crystal growth cavity (2). The reaction device also includes a top wall guide plate (12) disposed on the top of the flow guiding cavity (1). The top wall guide plates (12) of the two flow guiding cavities (1) are the same, so that the top wall guide plate (12) forms the top wall of the two flow guiding cavities (1) and the crystal growth cavity (2). The first heating element includes a top wall guide plate heater (6) built into the top wall guide plate (12). The reaction device also includes a flow divider extending horizontally in the flow guide cavity (1), and a gas passage is provided on one side of the flow divider, thereby forming two first gas passages extending in a bent shape in the two flow guide cavities (1) respectively. The first heating element also includes a flow divider heater built into the flow divider. The crystal growth cavity (2) is also provided with a fluid guide (23), which is located above the base (22). The second gas channel is formed in the fluid guide (23), and the second heating element includes a fluid guide heater (7) built into the fluid guide (23).

2. The silicon carbide chemical vapor deposition apparatus as described in claim 1, characterized in that: The top wall guide plate heater (6) is a plurality of heaters that are equally spaced within the top wall guide plate (12), and the distance between two adjacent top wall guide plate heaters (6) is not greater than 1 / 8 of the length of a single top wall guide plate heater (6).

3. The silicon carbide chemical vapor deposition apparatus as described in claim 1, characterized in that: The shunt heaters are multiple heaters that are equally spaced within the shunt, and the distance between two adjacent shunt heaters is no greater than 1 / 4 of the length of a single shunt heater.

4. The silicon carbide chemical vapor deposition apparatus as described in claim 1, characterized in that: The flow divider includes a first flow divider plate (15) and a second flow divider plate (16). The first flow divider plate (15) and the second flow divider plate (16) are arranged from top to bottom in the flow guide cavity (1). The gas passage includes a first channel on one side of the first flow divider plate (15) and a second channel on the opposite side of the second flow divider plate (16), thereby forming two first gas passages extending in a bent shape in the two flow guide cavities (1). The flow divider heater includes a first flow divider plate heater (3) built into the first flow divider plate (15) and a second flow divider plate heater (4) built into the second flow divider plate (16).

5. The silicon carbide chemical vapor deposition apparatus as described in claim 4, characterized in that: The reaction device also includes side wall guide plates (13) disposed on both sides of the flow guiding cavity (1) and bottom wall guide plates (14) disposed at the bottom of the flow guiding cavity (1). The distance between the top wall guide plate (12) and the first flow dividing plate (15), the distance between the first flow dividing plate (15) and the second flow dividing plate (16), and the distance between the second flow dividing plate (16) and the bottom wall guide plate (14) are all not greater than 1 / 4 of the distance between the two side wall guide plates (13).

6. The silicon carbide chemical vapor deposition apparatus as described in claim 1, characterized in that: The reaction apparatus also includes a heat insulation layer (8) disposed outside the flow guiding cavity (1) and the crystal growth cavity (2), and an outer cavity (9) disposed outside the heat insulation layer (8).

7. A method for silicon carbide chemical vapor deposition reaction, characterized in that, The method using a silicon carbide chemical vapor deposition apparatus as described in any one of claims 1-6 includes the following steps: Step S1: Using the same gas introduction process, equal amounts of reaction precursor gas, reducing gas, and carrier gas are introduced into the flow guiding cavities (1) on both sides of the crystal growth cavity (2). The reaction precursor gas is methyltrichlorosilane, the reducing gas is hydrogen, and the carrier gas is argon. Step S2: After the reaction precursor gas is uniformly decomposed in the flow guide cavity (1), its pyrolysis products are transferred to the crystal growth cavity (2) and deposited on the silicon carbide substrate placed on the deposition platform. The tail gas after the reaction is then discharged from the crystal growth cavity (2).

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