Polycrystalline silicon carbide growth device and growth method

Abstract

The present invention relates to the technical field of polycrystalline silicon carbide growth, and in particular to a polycrystalline silicon carbide growth device and a growth method, wherein the polycrystalline silicon carbide growth device includes a growth furnace, a wafer boat, a gas homogenizing component, a gas supply component and a heating component; in the same time period, corresponding polycrystalline silicon carbide films can be formed on the surfaces of multiple layers of wafers, respectively, thereby improving production efficiency. The gas homogenizing component is installed on the wafer boat, and can diffuse the mixed gas to the surface of each layer of wafer. On the one hand, the wafer boat is used as a carrier of the wafer; on the other hand, the wafer boat is also used as a carrier of the gas homogenizing component. Compared with the traditional polycrystalline silicon carbide growth device, the wafer boat and the gas homogenizing component are organically combined, and the same gas environment can be quickly formed around each layer of wafer. In this way, it is beneficial to improve the film forming efficiency, and it is also beneficial to keep the thickness of the silicon carbide film on the surface of each layer of wafer as consistent as possible, thereby ensuring the film forming quality of the silicon carbide film on the surface of each layer of wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of polycrystalline silicon carbide growth, and in particular to a polycrystalline silicon carbide growth device and a growth method. Background Art

[0002] Silicon carbide is a semiconductor material with excellent mechanical, electrical and chemical properties. Various devices made of this material can keep running in harsh environments. In recent years, semiconductor components made of silicon carbide materials, such as MOSFET (Metal Oxide Semiconductor Field Effect Transistor), MEMS (Micro Electro Mechanical System), SBD (Schottky Barrier Diode), IGBT (Insulate Gate Bipolar Transistor), etc., have excellent properties such as high temperature resistance, high voltage resistance, low energy loss and high radiation resistance, making silicon carbide one of the most promising materials in the field of semiconductor materials. In particular, polycrystalline silicon carbide, as a structural material, can be used as a sacrificial layer and mask layer to create more complex multi-layer silicon carbide devices.

[0003] In the early days, silicon carbide films were usually deposited using atmospheric pressure chemical vapor deposition reactors. In recent years, with the successful development of deposition technology, low-pressure chemical vapor deposition has been proven to be a feasible method for producing high-quality silicon carbide films at low substrate temperatures. Whether using a horizontal growth furnace to form a silicon carbide film on the surface of a wafer or a vertical growth furnace to form a silicon carbide film on the surface of a wafer, the film quality cannot meet higher requirements.

[0004] Therefore, how to further improve the film formation quality of silicon carbide thin films has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] The present invention provides a polycrystalline silicon carbide growing device and a growing method, which are used to solve the problem of how to further improve the film forming quality of silicon carbide thin films.

[0006] In one aspect, the present invention provides a polycrystalline silicon carbide growth device, comprising:

[0007] Growth furnace;

[0008] A wafer boat is placed in the growth furnace and is used to carry multiple layers of wafers;

[0009] The gas homogenization component is installed on the wafer boat and can diffuse the mixed gas to the surface of each layer of wafer;

[0010] A gas supply component is connected to the gas homogenizing component, and is used to mix the carrier gas and the material gas to form a mixed gas, and to deliver the mixed gas to the gas homogenizing component;

[0011] The heating assembly is installed on the growth furnace and is used to heat the wafer boat.

[0012] In some embodiments, the wafer boat includes:

[0013] A base having a first diversion cavity formed therein;

[0014] A top plate, arranged above the base;

[0015] There are four columns, which are evenly distributed around the circumference of the base; a plurality of wafer clamping grooves are evenly formed on the side wall of each column in the vertical direction; the bottom ends of three of the columns are fixedly mounted on the base, and the top ends are fixedly mounted on the top plate; the top end of another column is detachably mounted on the base, and the top end is detachably mounted on the top plate; a shunt channel connected to the first shunt cavity is formed inside each column;

[0016] The gas homogenization components include:

[0017] A flow-dividing ball is installed in the first flow-dividing cavity, and a plurality of first air outlet holes are formed on the side wall thereof, which are connected with the air supply assembly;

[0018] There are multiple gas uniforming plates evenly distributed in the vertical direction; the edge of each gas uniforming plate is fixedly connected to each column; a wafer accommodating cavity is formed between every two gas uniforming plates; a second diversion cavity is formed inside each gas uniforming plate and is respectively connected to the diversion channels on the four sides; a plurality of second air outlet holes are formed on the top surface and / or the bottom surface of each gas uniforming plate and are respectively connected to the second diversion cavity.

[0019] In some embodiments, the gas supply assembly includes:

[0020] The gas premixing chamber is connected to the gas homogenizing component and is used for mixing the carrier gas and the material gas to form a mixed gas and conveying the mixed gas to the gas homogenizing component.

[0021] In some embodiments, the gas supply assembly further comprises:

[0022] A mixed gas supply pipeline, used for connecting the gas premixing chamber and the gas homogenizing component;

[0023] A carrier gas supply pipeline is connected to the gas premixing chamber and is used to supply carrier gas to the gas premixing chamber;

[0024] A carbon source gas supply pipeline is connected to the gas premixing chamber and is used to supply the carbon source gas to the gas premixing chamber;

[0025] A silicon source gas supply pipeline is connected to the gas premixing chamber and is used to supply silicon source gas to the gas premixing chamber;

[0026] The oxygen supply pipeline is communicated with the gas premixing chamber and is used for supplying oxygen to the gas premixing chamber.

[0027] In some of these embodiments, the heating element is a high frequency heating coil, a resistive heater, or a heating lamp.

[0028] In some of the embodiments, an exhaust passage is formed in a side wall of the growth furnace;

[0029] Also includes:

[0030] The air extraction component is communicated with the exhaust passage.

[0031] In some of these embodiments, the growth furnace is a vertical furnace.

[0032] On the other hand, the present invention further provides a polycrystalline silicon carbide growth method, which is implemented using the polycrystalline silicon carbide growth device provided in any of the above embodiments, and includes the following steps:

[0033] S1. Pre-treating the surface of the wafer;

[0034] S2, depositing a first silicon carbide layer on the surface of the pretreated wafer;

[0035] S3, converting the first silicon carbide layer into a silicon oxide layer;

[0036] S4, depositing a second silicon carbide layer on the surface of the silicon oxide layer;

[0037] S5. Cool the wafer to room temperature.

[0038] In some of the embodiments, the thickness of the silicon oxide layer is 50 nm-300 nm.

[0039] In some of the embodiments, the second silicon carbide layer has a thickness of 50 nm-1000 nm.

[0040] The beneficial effects of the present invention are as follows: The polycrystalline silicon carbide growth device of the present invention is provided with a growth furnace, a wafer boat, a uniform gas assembly, a gas supply assembly and a heating assembly, and the growth furnace provides a growth space for the formation of a polycrystalline silicon carbide film. The wafer boat is used to carry multiple layers of wafers. In the same time period, corresponding polycrystalline silicon carbide films can be formed on the surfaces of the multiple layers of wafers respectively, thereby improving production efficiency. The uniform gas assembly is installed on the wafer boat, and can diffuse the mixed gas to the surface of each layer of wafer. On the one hand, the wafer boat is used as a carrier of the wafer; on the other hand, the wafer boat is also used as a carrier of the uniform gas assembly, which is beneficial to the layout of the uniform gas assembly. Compared with the traditional polycrystalline silicon carbide growth device, the wafer boat and the uniform gas assembly are organically combined, and the same gas environment can be quickly formed around each layer of wafer. In this way, it is beneficial to improve the film forming efficiency, and it is beneficial to keep the thickness of the silicon carbide film on the surface of each layer of wafer as consistent as possible, thereby ensuring the film forming quality of the silicon carbide film on the surface of each layer of wafer. The gas supply assembly is connected to the uniform gas assembly, and is used to mix the carrier gas and the material gas to form a mixed gas, and to convey the mixed gas to the uniform gas assembly. The heating component is installed on the growth furnace and is used to heat the wafer boat and the wafer to raise the temperature to the growth temperature of the polycrystalline silicon carbide film, which is beneficial to the formation of the polycrystalline silicon carbide film. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a cross-sectional view of a polycrystalline silicon carbide growth device of the present invention along the axial direction;

[0042] Figure 2 yes Figure 1 A partial enlarged view of the middle A area;

[0043] Figure 3 yes Figure 1 A top view of a gas distribution disk in a polycrystalline silicon carbide growth apparatus is shown.

[0044] Figure 4 is a transmission electron microscope image of the product.

[0045] In the accompanying drawings, 110, growth furnace; 111, exhaust channel; 120, crystal boat; 121, base; 1211, first diversion chamber; 122, top plate; 123, column; 1231, diversion channel; 130, gas uniformizing assembly; 131, diversion ball; 132, gas uniformizing disk; 1321, second diversion chamber; 1322, second gas outlet; 140, gas supply assembly; 141, gas premixing chamber; 142, mixed gas supply pipeline; 143, carrier gas supply pipeline; 144, carbon source gas supply pipeline; 145, silicon source gas supply pipeline; 146, oxygen supply pipeline; 150, heating assembly. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] As described in the background technology, in the early days, silicon carbide films were usually deposited using atmospheric pressure chemical vapor deposition reactors. In recent years, with the successful development of deposition technology, low-pressure chemical vapor deposition has been proven to be a feasible method for producing high-quality silicon carbide films under low substrate temperatures. Whether a horizontal growth furnace is used to form a silicon carbide film on the surface of a wafer, or a vertical growth furnace is used to form a silicon carbide film on the surface of a wafer, the film quality cannot meet higher requirements. Therefore, how to further improve the film quality of silicon carbide films has become a technical problem that needs to be solved urgently by those skilled in the art.

[0048] To solve the above problems, refer to Figure 1 , Figure 2 and Figure 3 On the one hand, the present invention provides a polycrystalline silicon carbide growth device, including a growth furnace 110, a wafer boat 120, a gas homogenizing assembly 130, a gas supply assembly 140 and a heating assembly 150. It should be noted that the wafer is used as a substrate, the size is 100mm-300mm, and the material is Si, SiC or graphite. The growth furnace 110 provides a growth space for the formation of a polycrystalline silicon carbide film. The wafer boat 120 is arranged in the growth furnace 110. The wafer boat 120 is used to carry multiple layers of wafers. In the same time period, corresponding polycrystalline silicon carbide films can be formed on the surfaces of the multiple layers of wafers, respectively, thereby improving production efficiency. The gas homogenizing assembly 130 is installed on the wafer boat 120, and can diffuse the mixed gas to the surface of each layer of wafer. On the one hand, the wafer boat 120 is used as a carrier of the wafer; on the other hand, the wafer boat 120 is also used as a carrier of the gas homogenizing assembly 130, which is beneficial to the layout of the gas homogenizing assembly 130. Compared with the traditional polycrystalline silicon carbide growth device, the wafer boat 120 and the gas homogenizing assembly 130 are organically combined, and can quickly form the same gas environment around each layer of wafers. In this way, it is beneficial to improve the film forming efficiency, and it is also beneficial to keep the thickness of the silicon carbide film on the surface of each layer of wafer as consistent as possible, thereby ensuring the film forming quality of the silicon carbide film on the surface of each layer of wafer. The gas supply assembly 140 is connected to the gas homogenizing assembly 130, and is used to mix the carrier gas and the material gas to form a mixed gas, and to convey the mixed gas to the gas homogenizing assembly 130. The heating assembly 150 is installed on the growth furnace 110, and is used to heat the wafer boat 120 and the wafer, and raise the temperature to the growth temperature of the polycrystalline silicon carbide film, which is beneficial to the formation of the polycrystalline silicon carbide film.

[0049] Preferably, the growth furnace 110 is a vertical furnace tube, including an inner tube and an outer tube. The inner tube is made of graphite, silicon carbide or quartz. The outer tube is made of silicon carbide or quartz.

[0050] Preferably, the wafer boat 120 is a vertical wafer boat 120 made of graphite, silicon carbide or quartz. The wafer boat 120 can carry 25 to 150 wafers at a time.

[0051] Specifically, in the exemplary embodiment, the wafer boat 120 includes a base 121, a top plate 122 and four columns 123. The bottom surface of the base 121 is an arc-shaped surface, and a first diversion cavity 1211 is formed inside. The top plate 122 is arranged above the base 121. The four columns 123 are evenly distributed around the circumference of the base 121. A plurality of wafer clamping grooves are evenly formed on the side wall of each column 123 in the vertical direction. Each wafer clamping groove is used to clamp a layer of wafers. The bottom ends of three of the columns 123 are respectively fixedly mounted on the base 121, and the top ends are respectively fixedly mounted on the top plate 122. The top end of another column 123 is detachably mounted on the base 121 by screwing, clamping, etc., and the top end is detachably mounted on the top plate 122 by screwing, clamping, etc. Here, it should be noted that when each layer of wafers is loaded into the wafer boat 120 by means of a manipulator, one of the columns 123 is in a state of being separated from the base 121 and the top plate 122. After the wafer installation is completed, the column 123 is connected to the base 121 and the top plate 122 respectively. A shunt channel 1231 connected to the first shunt chamber 1211 is formed inside each column 123. The gas homogenizing assembly 130 includes a shunt ball 131 and a plurality of gas homogenizing disks 132. The shunt ball 131 is installed in the first shunt chamber 1211, and a plurality of first air outlets are formed on the side wall, which are connected to the gas supply assembly 140. The shunt ball 131 is conducive to maintaining the same flow rate of mixed gas in each shunt channel 1231. The plurality of gas homogenizing disks 132 are evenly distributed in the vertical direction. The edges of each gas homogenizing disk 132 are fixedly connected to each column 123 respectively. A wafer accommodating cavity for accommodating wafers is formed between every two gas homogenizing disks 132. A second shunt chamber 1321 is formed inside each gas-distributing disk 132, which is respectively connected to the shunt channels 1231 on the four sides. A plurality of second air outlets 1322 are formed on the top surface and / or the bottom surface of each gas-distributing disk 132, which are respectively connected to the second shunt chamber 1321. It should be noted that the mixed gas from the gas supply assembly 140 flows through the shunt ball 131 into the first shunt chamber 1211. Since the shunt ball 131 is arranged in the first shunt chamber 1211, the flow rate of the mixed gas in each shunt channel 1231 remains consistent. Then, the mixed gas flowing through the shunt channels 1231 of the four columns 123 flows from the four sides of each gas-distributing disk 132 into the second shunt chamber 1321 of each gas-distributing disk 132, and then flows to the surface of each layer of wafers through the second air outlet 1322. On the whole, there is no large-volume shielding structure on the flow route of the mixed gas, and the same gas environment can be quickly formed around each layer of wafers.

[0052] Preferably, the number of the gas uniforming disks 132 is 26-151.

[0053] Specifically, in the exemplary embodiment, the gas supply assembly 140 includes a gas premixing chamber 141, a mixed gas supply pipeline 142, a carrier gas supply pipeline 143, a carbon source gas supply pipeline 144, a silicon source gas supply pipeline 145, and an oxygen supply pipeline 146. The gas premixing chamber 141 is connected to the diverter ball 131 of the gas homogenizing assembly 130, and is used to mix the carrier gas and the material gas to form a mixed gas, and to deliver the mixed gas to the diverter ball 131 of the gas homogenizing assembly 130. It should be noted that the material gas refers to the carbon source gas, the silicon source gas, and the oxygen. The mixed gas supply pipeline 142 is used to connect the gas premixing chamber 141 and the diverter ball 131 of the gas homogenizing assembly 130. The carrier gas supply pipeline 143 is connected to the gas premixing chamber 141, and is used to supply the carrier gas to the gas premixing chamber 141. The carbon source gas supply pipeline 144 is connected to the gas premixing chamber 141, and is used to supply the carbon source gas to the gas premixing chamber 141. The silicon source gas supply line 145 is in communication with the gas premixing chamber 141 for supplying the silicon source gas to the gas premixing chamber 141. The oxygen supply line 146 is in communication with the gas premixing chamber 141 for supplying the oxygen to the gas premixing chamber 141.

[0054] Preferably, the mixed gas supply pipeline 142 is provided with a first electromagnetic switch valve for controlling the on-off of the pipeline and a first flow control valve for controlling the flow.

[0055] Preferably, the carrier gas supply pipeline 143 is provided with a second electromagnetic switch valve for controlling the on-off of the pipeline and a second flow control valve for controlling the flow.

[0056] Preferably, the carbon source gas supply pipeline 144 is provided with a third electromagnetic switch valve for controlling the on-off of the pipeline and a third flow control valve for controlling the flow.

[0057] Preferably, the silicon source gas supply pipeline 145 is provided with a fourth electromagnetic switch valve for controlling the on-off of the pipeline and a fourth flow control valve for controlling the flow.

[0058] Preferably, the oxygen supply pipeline 146 is provided with a fifth electromagnetic switch valve for controlling the on-off of the pipeline and a fifth flow control valve for controlling the flow.

[0059] Preferably, the carrier gas comprises H 2 , Ar, N 2 , HCl, F 2 At least one of them.

[0060] Preferably, the carbon source gas comprises C 3 H 8 (5%H 2 ), C 2 H 4 (5%H 2 ), C 2 H2 (5%H 2 ), CF 4 (5%F 2 ), C 2 F 6 (5%F 2 ), C 3 F 8 (5%F 2 ), C 4 F 6 , C 4 F 8 , C 5 F 8 , CHF 3 , CH 2 F 2 , CH 3 F and C 2 HF 5 At least one of the above, with a flow rate between 100 sccm and 500 sccm.

[0061] Preferably, the silicon source gas comprises SiH 4 、SiH 3 F、SiH 2 F 2 、SiHF 3 、SiF 4 、SiH 2 Cl 2 , at least one of methyltrichlorosilane and tetramethylsilane, with a flow rate between 10 sccm and 100 sccm.

[0062] Preferably, the heating component 150 is a high-frequency heating coil, a resistance heater or a heating lamp, and the temperature control range is 700°C-1000°C and the temperature control accuracy is ±0.5°C.

[0063] Specifically, in the exemplary embodiment, an exhaust channel 111 is formed in the side wall of the growth furnace 110. The polycrystalline silicon carbide growth device further includes an exhaust assembly. The exhaust assembly is connected to the exhaust channel 111. After the mixed gas rises to the top of the growth furnace 110 in the growth furnace 110, the flow direction is reversed and begins to descend. With the help of the exhaust assembly, the mixed gas is discharged from the growth furnace 110 along the exhaust channel 111. The pressure control range is 0.1torr-10torr, and the pressure control accuracy is ±0.02torr.

[0064] Preferably, the air extraction assembly includes an air extraction pump and an air extraction pipeline. The air extraction pump is connected to the exhaust channel 111 through the air extraction pipeline to provide power for the gas flow.

[0065] Preferably, the air extraction pipeline is provided with a sixth electromagnetic switch valve for controlling the on-off of the pipeline and a sixth flow control valve for controlling the flow.

[0066] On the other hand, the present invention further provides a polycrystalline silicon carbide growth method, which is implemented using the polycrystalline silicon carbide growth device provided in any of the above embodiments, and includes the following steps:

[0067] S1. Pre-treating the surface of the wafer.

[0068] In this step, the surface of the wafer is pretreated to remove organic and metal impurities on the surface of the wafer.

[0069] S2. Depositing a first silicon carbide layer on the surface of the pretreated wafer.

[0070] It should be noted that the first silicon carbide layer can be formed in a growth furnace 110 or other equipment.

[0071] S3. Convert the first silicon carbide layer into a silicon oxide layer.

[0072] In this step, a wafer with a first silicon carbide layer deposited on the surface is placed in a growth furnace 110 or other equipment. A mixed gas of oxygen and carrier gas is introduced into the growth furnace 110 or other equipment. At high temperature, the first silicon carbide layer is transformed into a silicon oxide layer. The thickness of the silicon oxide layer is 50nm-300nm.

[0073] S4. Depositing a second silicon carbide layer on the surface of the silicon oxide layer.

[0074] In this step, a wafer with a silicon oxide layer deposited on the surface is placed in a growth furnace 110. The temperature in the growth furnace 110 is raised to 800°C-900°C, and then the growth furnace 110 is evacuated. Next, a mixed gas of a carrier gas, a carbon source gas, and a silicon source gas is introduced into the growth furnace 110, and the pressure in the growth furnace 110 is maintained at 0.5torr-1torr. Under high temperature and low pressure, a second silicon carbide layer with a thickness of 50nm-1000nm is deposited on the surface of the silicon oxide layer. The second silicon carbide layer is a polycrystalline silicon carbide layer.

[0075] S5. Cool the wafer to room temperature.

[0076] In this step, after the second silicon carbide layer is deposited, the supply of the carbon source gas and the silicon source gas is stopped, and the carrier gas is continuously introduced into the growth furnace 110 to restore the pressure in the growth furnace 110 to normal pressure (101.325 kPa). Next, the wafer is transferred from the growth furnace 110 to the wafer loading and unloading chamber for cooling. The cooling gas is N 2 During the cooling process, the oxygen concentration in the wafer loading and unloading chamber needs to be controlled until the wafer is cooled to room temperature (25°C).

[0077] On the whole, the polycrystalline silicon carbide film produced by the above method and device has good compactness and excellent uniformity. Since silicon oxide is selected as the intermediate layer, the dislocation and defects of the polycrystalline silicon carbide growth interface are greatly reduced, the lattice mismatch rate between the wafer and the polycrystalline silicon carbide film is greatly reduced, and the adhesion of the polycrystalline silicon carbide film is increased, which not only reduces the stress of the polycrystalline silicon carbide film, but also greatly improves the film quality.

[0078] In some of the applications, first, the surface of a 200 mm silicon wafer is pretreated to remove organic and metal impurities on the surface of the wafer. Next, a first silicon carbide layer is deposited on the surface of the pretreated wafer. Then, the wafer with the first silicon carbide layer deposited on the surface is placed in a growth furnace 110 or other equipment. Oxidation and N are introduced into the growth furnace 110 or other equipment. 2 The first silicon carbide layer is transformed into a silicon oxide layer at a high temperature. The thickness of the silicon oxide layer is 200 nm. Then, the wafer with the silicon oxide layer deposited on the surface is placed in the growth furnace 110. The temperature in the growth furnace 110 is raised to 900°C, and then the growth furnace 110 is evacuated. Then, N 2 、SiH 2 Cl 2 and C 2 H 2 (5%H 2 ) and the pressure in the growth furnace 110 is maintained at 0.5tor. In a high temperature and low pressure environment, a second silicon carbide layer is deposited on the surface of the silicon oxide layer. Finally, the wafer is cooled to room temperature. 2 、SiH 2 Cl 2 and C 2 H 2 (5%H 2 ) gas purity is greater than 99.999%. Figure 4 This is a transmission electron microscope image of the product, which shows the second silicon carbide layer, oxide layer and wafer from top to bottom. The stress of the second silicon carbide layer is 100MPa-200MPa, which is significantly reduced.

[0079] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0080] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0081] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0083] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for growing polycrystalline silicon carbide, characterized in that: This is achieved using a polycrystalline silicon carbide growth device; The polycrystalline silicon carbide growing device comprises: Growth furnace; A wafer boat, arranged in the growth furnace, for carrying multiple layers of wafers; A gas homogenizing component, installed on the wafer boat, capable of diffusing the mixed gas to the surface of each layer of the wafer; A gas supply component, connected to the gas homogenizing component, for mixing the carrier gas and the material gas to form the mixed gas, and delivering the mixed gas to the gas homogenizing component; A heating assembly, installed on the growth furnace, for heating the wafer boat; The wafer boat comprises: The base has an arc-shaped bottom surface and a first flow distribution cavity formed inside; A top plate, arranged above the base; There are four columns, which are evenly distributed around the circumference of the base; a plurality of wafer clamping grooves are evenly formed on the side wall of each column in the vertical direction; the bottom ends of three of the columns are respectively fixedly mounted on the base, and the top ends are respectively fixedly mounted on the top plate; the top end of another column is detachably mounted on the base, and the top end is detachably mounted on the top plate; a shunt channel connected to the first shunt cavity is formed inside each column; The gas homogenizing component comprises: A flow-dividing ball is installed in the first flow-dividing cavity, and a plurality of first air outlet holes are formed on the side wall thereof, and is connected with the air supply assembly; There are multiple gas-distributing plates evenly distributed in the vertical direction; the edge of each gas-distributing plate is respectively fixedly connected to each of the pillars; a wafer accommodating cavity is formed between every two gas-distributing plates; a second flow-dividing cavity is formed inside each gas-distributing plate and is respectively connected to the flow-dividing channels on four sides; a plurality of second air outlets are formed on the top surface and / or the bottom surface of each gas-distributing plate and are respectively connected to the second flow-dividing cavity; The polycrystalline silicon carbide growth method comprises the following steps: S1. Pre-treating the surface of the wafer; S2, depositing a first silicon carbide layer on the surface of the pretreated wafer; S3, placing the wafer with the first silicon carbide layer deposited on the surface in a growth furnace; introducing a mixed gas of oxygen and carrier gas into the growth furnace; at a high temperature, the first silicon carbide layer is transformed into a silicon oxide layer; the thickness of the silicon oxide layer is 50nm-300nm; S4, placing the wafer with the silicon oxide layer deposited on the surface in the growth furnace; raising the temperature in the growth furnace to 800°C-900°C; then, evacuating the growth furnace; then, introducing a mixed gas of carrier gas, carbon source gas and silicon source gas into the growth furnace, and maintaining the pressure in the growth furnace at 0.5torr-1torr, and depositing a second silicon carbide layer with a thickness of 50nm-1000nm on the surface of the silicon oxide layer in a high temperature and low pressure environment; S5, cooling the wafer to room temperature.

2. The polycrystalline silicon carbide growth method according to claim 1, characterized in that: The gas supply assembly comprises: The gas premixing chamber is connected to the gas homogenizing component and is used for mixing the carrier gas and the material gas to form the mixed gas and delivering the mixed gas to the gas homogenizing component.

3. The polycrystalline silicon carbide growth method according to claim 2, characterized in that: The air supply assembly also includes: A mixed gas supply pipeline, used for connecting the gas premixing chamber and the gas homogenizing component; a carrier gas supply pipeline, connected to the gas premixing chamber, and used for supplying carrier gas to the gas premixing chamber; a carbon source gas supply pipeline, connected to the gas premixing chamber, and used for supplying the carbon source gas to the gas premixing chamber; a silicon source gas supply pipeline, connected to the gas premixing chamber, and used for supplying silicon source gas to the gas premixing chamber; The oxygen supply pipeline is communicated with the gas premixing chamber and is used for supplying oxygen to the gas premixing chamber.

4. The polycrystalline silicon carbide growth method according to claim 1, characterized in that: The heating component is a high-frequency heating coil, a resistance heater or a heating lamp.

5. The polycrystalline silicon carbide growth method according to claim 1, characterized in that: An exhaust passage is formed in the side wall of the growth furnace; The polycrystalline silicon carbide growth device further comprises: An air extraction component is communicated with the exhaust passage.

6. The polycrystalline silicon carbide growth method according to claim 1, characterized in that: The growth furnace is a vertical furnace.

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