Epitaxial growth chamber for silicon carbide substrate

Abstract

The invention discloses an epitaxial growth chamber for a silicon carbide substrate. The growth chamber is divided into an upper furnace body and a lower furnace body from top to bottom; at least one heater is arranged in the upper furnace body and / or the lower furnace body; a rotating shaft rotating device is arranged below the lower furnace body, a rotating shaft is arranged above the rotating shaft rotating device, and the rotating shaft upwards penetrates through the lower furnace body; a hole is formed in the left side wall of the lower furnace body and is provided with a connecting neck to form a sheet loading and taking channel; a growth chamber flange is arranged at the outer end of the connecting neck; a base rotating shaft is arranged at the top of the rotating shaft; a base is arranged at the top of the base rotating shaft; a bearing ring mounting hole is formed in the base and used for containing a bearing ring, and the bearing ring is used for containing a substrate slice with the polished front face facing downwards. A second upper wall plate is arranged in the lower furnace body from top to bottom, a loading cavity is defined by the second isolation plate, the lower wall plate, the base and the upper wall plate, and the loading cavity and the piece loading and taking channel are communicated and located at the same height. According to the invention, the problem that wrappage defects are easy to generate in the manufacturing process of the silicon carbide epitaxial wafer is solved; thermal field installation in the epitaxial furnace is simplified, and use is convenient.

Description

Technical Field

[0001] The invention relates to an epitaxial growth chamber for a silicon carbide substrate. Background Art

[0002] As the foundation of the modern electronic information industry, the semiconductor industry is an important industry that supports the high-quality development of the national economy. The third-generation semiconductor refers to emerging semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) with wide bandgap (Eg>2.3eV) characteristics. Silicon carbide is the most mature third-generation semiconductor material currently. Silicon carbide devices have the advantages of small size, high power, high frequency, low energy consumption, low loss, and high voltage resistance. The current main application areas are various power supplies and servers, photovoltaic inverters, wind power inverters, on-board chargers for new energy vehicles, motor drive systems, DC charging piles, variable frequency air conditioners, rail transit, military industry, etc.

[0003] In practical applications, wide bandgap semiconductor devices are almost all made on epitaxial layers. The polished silicon carbide wafer itself is only used as a substrate. A silicon carbide or gallium nitride epitaxial layer of a certain thickness and resistivity is grown on its front side (polished surface) by chemical vapor deposition (CVD). The silicon carbide substrate plus the epitaxial layer is commonly known as a silicon carbide epitaxial wafer.

[0004] In terms of silicon carbide device design and manufacturing, SiC diodes are gradually being improved, but SiC MOS devices face many difficulties. One important aspect is to improve the quality of the silicon carbide epitaxial layer.

[0005] At present, there are three typical structures of CVD epitaxial furnace reaction chambers: Figure 1 , Figure 2 , Figure 3 ), which are hot wall horizontal type, wall temperature planetary type, and quasi-hot wall vertical type. The common feature of the three reaction chamber structures is that the reaction gas flows over the front side (polished surface) of the silicon carbide substrate and grows a silicon carbide epitaxial layer of a certain thickness and resistivity on the polished surface. Because the reaction temperature of growing a silicon carbide epitaxial layer on a silicon carbide substrate is high (about 1600°C), there is silicon carbide deposition on the inner wall of the reaction chamber, and the deposited silicon carbide particles will be drawn into the reaction gas. Silicon carbide particles will also be produced in the reaction gas due to chemical reactions. The particles in the reaction gas will fall on the epitaxial growth surface of the substrate, causing defects in the epitaxial layer grown subsequently. This type of defect is called epitaxial inclusions. Defects in epitaxial inclusions can cause subsequent processed devices to fail due to large leakage currents.

[0006] The current method to solve the problem of particle falling during epitaxial growth is to rotate the substrate at high speed during epitaxial growth (more than 500 rpm for a quasi-hot wall vertical epitaxial furnace and about 60 rpm for a hot wall horizontal epitaxial furnace) so that the particles leave the surface of the substrate under the action of centrifugal force. However, this does not effectively solve the problem of inclusions and may cause the substrate to vibrate too much, thereby reducing the epitaxial quality. Summary of the invention

[0007] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide an epitaxial growth chamber for a silicon carbide substrate.

[0008] The technical solution for achieving the technical purpose of the present invention is as follows: An epitaxial growth chamber for a silicon carbide substrate, the growth chamber is divided into an upper furnace body and a lower furnace body from top to bottom; at least one heater is provided in the upper furnace body and / or the lower furnace body; the outer wall of the lower furnace body is provided with a hydrogen and epitaxial growth gas inlet and outlet, which are connected to the epitaxial growth area; A shaft rotating device is provided below the lower furnace body, a shaft is provided above the shaft rotating device, and the shaft passes through the lower furnace body upwards; The left side wall of the lower furnace body is opened with a connecting neck to form a passage for loading and unloading the slices; the outer end of the connecting neck is provided with a growth chamber flange; A base rotating shaft is provided on the top of the rotating shaft, and a base is provided on the top of the base rotating shaft; a bearing ring mounting hole is provided on the base for placing a bearing ring, and the bearing ring is used for placing a substrate sheet with the polishing front side facing downward; The lower furnace body is provided with two upper wall plates, two isolation plates, and a lower wall plate from top to bottom. The base and the upper wall plate form a loading cavity, which is connected to the sheet loading and unloading channel and is at the same height; an epitaxial growth zone is formed between the isolation plate, the base, and the lower wall plate; the isolation plate and the base separate the sheet loading and unloading channel from the epitaxial growth zone, and the sheet loading and unloading channel is above the epitaxial growth zone.

[0009] The growth chamber is divided into an upper furnace body and a lower furnace body from top to bottom; at least one heater is provided in the upper furnace body and / or the lower furnace body; the outer wall of the lower furnace body is provided with a hydrogen and epitaxial growth gas inlet and outlet, which are connected to the epitaxial growth area; A shaft rotating device is provided below the lower furnace body, a shaft is provided above the shaft rotating device, and the shaft passes through the lower furnace body upwards; The left side wall of the lower furnace body is opened with a connecting neck to form a passage for loading and unloading the slices; the outer end of the connecting neck is provided with a growth chamber flange; A base rotating shaft is provided on the top of the rotating shaft, and a base is provided on the top of the base rotating shaft; a bearing ring mounting hole is provided on the base for placing a bearing ring, and the bearing ring is used for placing a substrate sheet with the polishing front side facing downward; The lower furnace body is provided with an isolation plate and a lower wall plate from top to bottom, and an epitaxial growth area is surrounded by the isolation plate, the base and the lower wall plate; the sheet loading and unloading channel is connected to the epitaxial growth area, and the sheet loading and unloading channel and the epitaxial growth area are at the same height, and sheets are loaded and unloaded in the epitaxial growth area.

[0010] The inner wall of the upper furnace body is provided with a top insulation layer and an upper insulation tube from top to bottom; the inner wall of the lower furnace body is provided with a bottom insulation layer and a lower insulation tube.

[0011] An upper heater is arranged inside the upper furnace body, and upper electrodes are symmetrically arranged on the upper part of the upper furnace body, and the upper electrodes are connected to the upper heater.

[0012] A lower heater is arranged inside the lower furnace body and is located below the lower wall plate. A lower electrode is arranged at the bottom of the lower furnace body and is connected to the lower heater. The base rotating shaft passes through the lower heater upward.

[0013] The base is provided with 2-20 bearing ring mounting holes, and the bearing ring mounting holes are evenly distributed on the base.

[0014] The outer wall of the lower furnace body is provided with a hydrogen and epitaxial growth gas inlet and an outlet. The hydrogen and epitaxial growth gas inlet is connected to an external gas distribution cabinet; the outlet is connected to an external vacuum pump.

[0015] The carrying ring is provided with an inner bevel, which contacts only the chamfered surface of the front edge of the substrate sheet, and is used for placing the substrate sheet with the polished front side facing downward.

[0016] The epitaxial furnace is not provided with a bearing ring, and the bearing ring mounting hole of the base is changed into an integrated substrate sheet mounting hole. The substrate sheet is directly mounted in the integrated substrate sheet mounting hole of the base by a sheet loading robot, with the polished front side facing downward.

[0017] Beneficial effects of the present invention:

[0018] An epitaxial growth chamber for a silicon carbide substrate is provided. The polished front side of the silicon carbide substrate is suspended downward, and a mixed gas of hydrogen and epitaxial growth gas flows from below along the polished front side of the substrate, and the required silicon carbide epitaxial layer is grown on the polished front side of the substrate. There is no problem of particles falling onto the epitaxial growth surface, and there is no need to rotate the substrate at high speed during the epitaxial growth process, thereby improving the rotation stability of the substrate during the epitaxial process. The problem of easy generation of inclusion defects during the manufacturing process of silicon carbide epitaxial wafers is effectively solved, and the resistivity and thickness uniformity of the epitaxial wafers are improved.

[0019] The applicant has previously applied for patents in the same field that solve similar technical problems (such as CN118497887A, "Resistance-heated epitaxial furnace and growth method for growing epitaxial layers on silicon carbide substrate sheets"; CN118064968A, "Induction-heated epitaxial furnace and growth method for growing epitaxial layers on silicon carbide substrate sheets"). In those solutions, the support ring is placed on a loading plate in a loading cage, and the loading cage is suspended in the upper furnace body through a rotating shaft. When the silicon carbide epitaxial furnace is actually used, the furnace chamber is frequently opened to clean the thermal field components in the furnace, and it is not very convenient to clean the loading cage suspended in the upper furnace body. Compared with the applicant's previous inventions, the present invention has the advantages of simplifying the thermal field installation in the epitaxial furnace and being more convenient in actual use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the hot wall horizontal CVD epitaxial furnace reaction chamber.

[0021] Figure 2 Schematic diagram of the structure of the reaction chamber of a warm-wall planetary CVD epitaxial furnace.

[0022] Figure 3 Schematic diagram of the structure of the reaction chamber of a quasi-hot-wall vertical CVD epitaxial furnace.

[0023] Figure 4 A schematic diagram of the structural plan layout of a complete epitaxial furnace formed by the present invention.

[0024] Figure 5 A cross-sectional view of the epitaxial growth chamber of the present invention along the direction of loading and unloading wafers.

[0025] Figure 6 A cross-sectional view of the epitaxial growth chamber of the present invention along the air inlet and the air outlet.

[0026] Figure 7 Top view of the base (three-piece).

[0027] Figure 8 Sectional view of the base with the carrier ring mounted and the base rotation axis.

[0028] Fig. 9 A cross-sectional view of a base with integrated substrate sheet mounting holes and the base rotation axis.

[0029] Fig.10 Cross-sectional view of a carrier ring and a silicon carbide epitaxial substrate wafer mounted therein.

[0030] Fig.11 A partial cross-sectional view of a carrier ring and a silicon carbide epitaxial substrate wafer mounted therein.

[0031] Fig.12 A cross-sectional view of the epitaxial growth chamber of the present invention along the direction of loading and unloading wafers.

[0032] Fig.13A cross-sectional view along the direction of loading and unloading the wafer when the epitaxial growth chamber of the present invention is installed with only one lower resistance heater.

[0033] Fig.14 A cross-sectional view along the direction of loading and unloading the wafer when the epitaxial growth chamber of the present invention is only equipped with one upper resistance heater.

[0034] Fig.15 A cross-sectional view along the direction of loading and unloading the wafer when the epitaxial growth chamber of the present invention is installed with only one lower resistance heater.

[0035] Fig.16 A cross-sectional view along the direction of loading and unloading the wafer when the epitaxial growth chamber of the present invention is only equipped with one upper resistance heater.

[0036] Fig.17 A cross-sectional view along the direction of loading and unloading the wafer when two induction heaters are installed in the epitaxial growth chamber of the present invention.

[0037] Fig.18 A cross-sectional view along the direction of loading and unloading the wafer when two induction heaters are installed in the epitaxial growth chamber of the present invention.

[0038] Fig.19 A cross-sectional view along the direction of loading and unloading the wafer when an upper induction heater is installed in the epitaxial growth chamber of the present invention.

[0039] Fig. 20 A cross-sectional view along the direction of loading and unloading the wafer when an upper induction heater is installed in the epitaxial growth chamber of the present invention.

[0040] Fig.21 A cross-sectional view along the direction of loading and unloading the wafer when a lower induction heater is installed in the epitaxial growth chamber of the present invention.

[0041] Fig. 22 A cross-sectional view along the direction of loading and unloading the wafer when a lower induction heater is installed in the epitaxial growth chamber of the present invention.

[0042] In the figure, cooling chamber 1, wafer holder 2, wafer loading chamber 3, wafer holder 1 4, transmission chamber 5, manipulator 6, transmission chamber flange 7, growth chamber flange 8, wafer loading and unloading channel 9, hydrogen and epitaxial growth gas inlet 10, lower wall plate 11, lower furnace body support 12, column 13, gas outlet 14, growth chamber 15, connecting neck 16, lower furnace body 17, isolation plate 18, lower heater 19, upper furnace body 20, upper insulation tube 21, top insulation layer 22, epitaxial growth area 23, upper electrode 24, rotating shaft 25, rotating shaft rotating device 26, The shaft lifting device 27, the lower column 28, the base rotating shaft 29, the upper heater 30, the substrate sheet 31, the upper wall plate 32, the upper furnace body lifting device 33, the hinge 34, the bearing ring 35, the lower insulation tube 36, the upper thermometer 37, the lower electrode 38, the furnace body bottom frame 39, the bottom insulation layer 40, the bearing ring mounting hole 41, the base 42, the loading cavity 43, the bearing ring positioning groove 44, the front edge chamfered surface 45, the polished front surface 46, the inner bevel 47, the bottom thermometer 48, and the integrated substrate sheet mounting hole 49. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0044] like Figure 5 , Figure 6 The epitaxial growth chamber for silicon carbide substrates shown in the figure comprises an upper furnace body 20 and a lower furnace body 17 from top to bottom; at least one heater is provided in the upper furnace body 20 and / or the lower furnace body 17; the outer wall of the lower furnace body 17 is provided with a hydrogen and epitaxial growth gas inlet 10 and an outlet 14, which are connected to the epitaxial growth area 23.

[0045] A shaft rotating device 26 is provided below the lower furnace body 17, a shaft 25 is provided above the shaft rotating device 26, and the shaft 25 passes through the lower furnace body 17 upward; a hole is opened on the left side wall of the lower furnace body 17, and a connecting neck 16 is provided to form a sheet loading and unloading channel 9; a growth chamber flange 8 is provided at the outer end of the connecting neck 16.

[0046] A base rotating shaft 29 is disposed on the top of the rotating shaft 25, and a base 42 is disposed on the top of the base rotating shaft 29; a bearing ring mounting hole 41 is provided on the base 42 for placing a bearing ring 35, and the bearing ring 35 is used to place the substrate sheet 31 with the polished front side 46 facing downward; The lower furnace body 17 is provided with an upper wall plate 48, an isolation plate 50, and a lower wall plate 11 from top to bottom. The base 42 and the upper wall plate 32 form a loading chamber 43, and the loading chamber 43 is connected to the sheet loading and unloading channel 9 and is at the same height; an epitaxial growth zone 23 is formed between the isolation plate 18, the base 42, and the lower wall plate 11; the isolation plate 18 and the base 42 separate the sheet loading and unloading channel 9 from the epitaxial growth zone 23, and the sheet loading and unloading channel 9 is above the epitaxial growth zone 23.

[0047] The height of the susceptor 42 remains unchanged during loading and unloading of wafers and epitaxial growth.

[0048] like Fig.12 The epitaxial growth chamber for silicon carbide substrate is shown, the growth chamber 15 is divided into an upper furnace body 20 and a lower furnace body 17 from top to bottom; at least one heater is provided in the upper furnace body 20 and / or the lower furnace body 17; the outer wall of the lower furnace body 17 is provided with a hydrogen and epitaxial growth gas inlet 10 and an outlet 14, which are connected to the epitaxial growth area 23; A shaft rotating device 26 is provided below the lower furnace body 17, a shaft 25 is provided above the shaft rotating device 26, and the shaft 25 passes through the lower furnace body 17 upward; a hole is opened on the left side wall of the lower furnace body 17, and a connecting neck 16 is provided to form a sheet loading and unloading channel 9; a growth chamber flange 8 is provided at the outer end of the connecting neck 16.

[0049] A base rotating shaft 29 is disposed on the top of the rotating shaft 25, and a base 42 is disposed on the top of the base rotating shaft 29; a bearing ring mounting hole 41 is provided on the base 42 for placing a bearing ring 35, and the bearing ring 35 is used to place the substrate sheet 31 with the polished front side 46 facing downward; The lower furnace body 17 is provided with an isolation plate 18 and a lower wall plate 11 from top to bottom, and an epitaxial growth area 23 is surrounded by the isolation plate 18, the base 42, and the lower wall plate 11. The loading and unloading channel 9 is connected to the epitaxial growth area 23, and the loading and unloading channel 9 and the epitaxial growth area 23 are at the same height, and the epitaxial growth area 23 is loaded and unloaded.

[0050] When loading or unloading the wafer, the susceptor 42 is lowered to the bottom of the epitaxial growth region 23, and when epitaxial growth is performed, the susceptor 42 is raised to the top of the epitaxial growth region 23.

[0051] like Figure 5 , Figure 6 , Fig.12 The epitaxial growth chamber for silicon carbide substrates shown in the figure has a top insulation layer 22 and an upper insulation tube 21 on the inner wall of the upper furnace body 20 from top to bottom; and a bottom insulation layer 40 and a lower insulation tube 36 on the inner wall of the lower furnace body 17.

[0052] like Figure 5 , Figure 6 , Fig.12 The epitaxial growth chamber for silicon carbide substrate is shown, wherein an upper heater 30 is arranged inside an upper furnace body 20 , and upper electrodes 24 are symmetrically arranged on the upper part of the upper furnace body 20 , and the upper electrodes 24 are connected to the upper heater 30 .

[0053] like Figure 5 , Figure 6 , Fig.12An epitaxial growth chamber for growing an epitaxial layer on a silicon carbide substrate is shown, wherein a lower heater 19 is provided inside a lower furnace body 17, and is located below a lower wall plate 11. A lower electrode 38 is provided at the bottom of the lower furnace body 17, and the lower electrode 38 is connected to the lower heater 19. A susceptor rotating shaft 29 passes through the lower heater 19 upward.

[0054] like Figure 7 , Figure 8 The epitaxial growth chamber for a silicon carbide substrate is shown, and 2-20 carrying ring mounting holes 41 are provided on a base 42 , and the carrying ring mounting holes 41 are evenly distributed on the base 42 .

[0055] like Figure 6 The epitaxial growth chamber for silicon carbide substrates shown in the figure has a hydrogen and epitaxial growth gas inlet 10 and an outlet 14 on the outer wall of the lower furnace body 17. The hydrogen and epitaxial growth gas inlet 10 is connected to an external gas distribution cabinet; the outlet 14 is connected to an external vacuum pump.

[0056] like Fig.10 , Fig.11 The epitaxial growth chamber for silicon carbide substrates shown in the figure has a carrying ring 35 with an inner bevel 47, which contacts only the front edge chamfered surface 45 of the substrate sheet 31 and is used to place the substrate sheet 31 with the polished front side 46 facing downward.

[0057] like Fig. 9 The epitaxial growth chamber shown in the figure is used for silicon carbide substrates. It is not equipped with a carrying ring 35. The carrying ring mounting hole 41 of the base 42 is changed into an integrated substrate sheet mounting hole 49. The substrate sheet 31 is directly mounted in the integrated substrate sheet mounting hole 49 of the base 42 by the loading robot 6, with the polished front side 46 facing downward.

[0058] The technical solution of the present invention that the wafer loading and unloading channel 9 is located above the epitaxial growth area 23 only uses a lower heater 19. Fig.13 shown.

[0059] The technical solution of the present invention that the wafer loading and unloading channel 9 is located above the epitaxial growth area 23 only uses a structural diagram of an upper heater 30 as shown in FIG. Fig.14 shown.

[0060] The technical solution of the present invention that the wafer loading and unloading channel 9 is at the same height as the epitaxial growth area 23, and only one lower heater 19 is used, as shown in the structural diagram. Fig.15 shown.

[0061] The technical solution of the present invention that the wafer loading and unloading channel 9 is at the same height as the epitaxial growth area 23 and only one upper heater 30 is used is shown in the structural diagram. Fig.16 shown.

[0062] like Figure 5, Figure 6 , Fig.12 , Fig.13 , Fig.14 , Fig.15 , Fig.16 As shown, both the upper heater 30 and the lower heater 19 employed are resistance heaters.

[0063] The technical solution of the present invention in which the wafer loading and unloading channel 9 is located above the epitaxial growth region 23, and two induction heaters (upper heater 30, lower heater 19) are used, is shown in the structural diagram as follows: Fig.18 shown.

[0064] The technical solution of the present invention in which the wafer loading and unloading channel 9 is located above the epitaxial growth region 23, uses an induction heater (upper heater 30) as shown in the structural diagram. Fig. 20 shown.

[0065] The technical solution of the present invention in which the wafer loading and unloading channel 9 is located above the epitaxial growth region 23, uses an induction heater (lower heater 19) as shown in the structural diagram. Fig. 22 shown.

[0066] The technical solution of the present invention that the wafer loading and unloading channel 9 is at the same height as the epitaxial growth area 23 uses two induction heaters (upper heater 30, lower heater 19) as shown in the structural diagram. Fig.17 shown.

[0067] The technical solution of the present invention that the wafer loading and unloading channel 9 is at the same height as the epitaxial growth area 23 adopts an induction heater (upper heater 30) as shown in the structural diagram. Fig.19 shown.

[0068] The technical solution of the present invention that the wafer loading and unloading channel 9 is at the same height as the epitaxial growth area 23 adopts an induction heater (lower heater 19) as shown in the structural diagram. Fig.21 shown.

[0069] like Figure 4 As shown, an epitaxial growth chamber for a silicon carbide substrate should be combined with a transfer chamber 5, a cooling chamber 1, and a loading chamber 3 in actual use to form an epitaxial furnace that can be actually used to grow epitaxial layers on silicon carbide substrates.

[0070] like Figure 5 , Figure 6 , Fig.12 As shown, an epitaxial growth chamber for a silicon carbide substrate is provided with an upper thermometer 37 and a bottom thermometer 48 for measuring temperature. like Figure 5 , Figure 6 The operation steps of an epitaxial growth chamber for a silicon carbide substrate for manufacturing a silicon carbide epitaxial wafer are as follows: 1) Maintain the temperature of the epitaxial growth zone 23 at 850-950° C. (This temperature is selected to balance production efficiency and prevent the wafer from bursting due to excessive thermal stress, and there may be a certain range, such as 850-950° C.), and pass hydrogen through the hydrogen and epitaxial growth gas inlet 10; 2) Place the carrier ring 35 on the wafer seat 4 in the wafer loading chamber 3, with the upper surface facing upward; Place the substrate wafer 31 on the carrier ring 35 manually or automatically, with the polished front side 46 for epitaxial layer growth facing downward, the chamfered surface 45 of the front edge of the substrate wafer 31 in contact with the inner bearing inclined surface 47 of the carrier ring 35, the back and front sides of the substrate wafer are parallel to the upper and lower surfaces of the carrier ring, and the polished front side 46 of the substrate wafer 31 does not contact with other objects, such as Fig.11 As shown, the polished front surface 46 is substantially flush with the lower surface of the carrying ring 35, and the height difference δ is in the range of 0-1 mm; 3) The loading and unloading direction of the base 42 is aligned with the loading and unloading direction of the wafer loading and unloading manipulator 6. The manipulator 6 in the transfer chamber 5 holds the edges of both sides of the lower surface of the carrying ring 35, and places the carrying ring 35 together with the substrate 31 thereon into the carrying ring mounting hole 41 on the base 42 through the loading chamber 3, the transfer chamber 5, the growth chamber flange 8, the loading and unloading passage 9, and the loading chamber 43. The lower surfaces of the carrying ring 35 and the base 42 are flush. The base 42 is filled with epitaxial substrates; 4) Raising the temperature of the epitaxial growth zone 23 to a set epitaxial growth temperature (the growth temperature of the silicon carbide epitaxial layer grown on the silicon carbide substrate is about 1600 degrees) at a set speed (5-100 degrees / minute); 5) The rotating shaft 25 drives the base 42 to rotate at a speed set for epitaxial growth (1-50 rpm); 6) introducing epitaxial growth gas (including but not limited to part or all of trichlorosilane, ethylene, hydrogen chloride, nitrogen, ammonia, etc.) from the hydrogen and epitaxial growth gas inlet 10 into the epitaxial growth region 23 and flowing toward the gas outlet 14, during which the mixed gas of hydrogen and epitaxial growth gas flows from the bottom of the substrate 31 along the polished front surface 46 of the substrate 31, and when a silicon carbide epitaxial layer of a set thickness grows on the polished front surface 46 of the substrate 31, the introduction of the epitaxial growth gas is stopped to end the epitaxial growth process; 7) reducing the temperature of the epitaxial growth zone 23 to 850-950°C at a set rate (5-100°C / min) and maintaining the temperature; 8) The rotation speed of the rotating shaft 25 is reduced to zero, and the loading and unloading direction of the base 42 is aligned with the loading and unloading direction of the loading and unloading robot 6; 9) The robot 6 in the transfer chamber sequentially delivers the carrier ring 35 and the epitaxial wafer thereon to the cooling chamber 1 and places them on the wafer holder 2 for cooling. After cooling, the robot 6 in the transfer chamber 5 transfers them to the wafer holder 1 4 of the wafer loading chamber 3 and then takes them out; 10) Repeat steps 1) to 9) to start processing the next batch of epitaxial wafers.

[0071] like Fig.12 As shown, the actual use steps of a variant of an epitaxial growth chamber for a silicon carbide substrate for manufacturing a silicon carbide epitaxial wafer are as follows: 1) Maintain the temperature of the epitaxial growth zone 23 at 850-950° C. (This temperature is selected to balance production efficiency and prevent the wafer from bursting due to excessive thermal stress, and there may be a certain range, such as 850-950° C.), and pass hydrogen through the hydrogen and epitaxial growth gas inlet 10; 2) Place the carrier ring 35 on the wafer seat 4 in the wafer loading chamber 3, with the upper surface facing upward; place the substrate wafer 31 on the carrier ring 35 manually or automatically, with the polished front side 46 for epitaxial layer growth facing downward, the chamfered surface 45 of the front edge of the substrate wafer 31 in contact with the inner bearing inclined surface 47 of the carrier ring 35, the back and front sides of the substrate wafer are parallel to the upper and lower surfaces of the carrier ring, the polished front side 46 of the substrate wafer 31 does not contact other objects, and the polished front side 46 is substantially flush with the lower surface of the carrier ring 35, and the value range of the height difference δ is 0-1 mm; 3) The base 42 is lowered to the loading and unloading position, and the loading and unloading direction of the base 42 is aligned with the loading and unloading direction of the wafer loading and unloading robot 6. The robot 6 in the transfer chamber 5 holds the edges of both sides of the lower surface of the carrying ring 35, and places the carrying ring 35 together with the substrate 31 thereon into the carrying ring mounting hole 41 on the base 42 through the loading chamber 3, the transfer chamber 5, the growth chamber flange 8, and the loading channel 9. The lower surfaces of the carrying ring 35 and the base 42 are flush. The base 42 is filled with epitaxial substrates; 4) Raising the temperature of the epitaxial growth zone 23 to a set epitaxial growth temperature (the growth temperature of the silicon carbide epitaxial layer grown on the silicon carbide substrate is about 1600 degrees) at a set speed (5-100 degrees / minute); 5) Raise the base 42 until the lower surface of the carrying ring 35 is flush with the lower surface of the isolation plate 18 and stops rising; 6) The rotating shaft 25 drives the base 42 to rotate at a speed set for epitaxial growth (1-50 rpm); 7) introducing epitaxial growth gas (including but not limited to part or all of trichlorosilane, ethylene, hydrogen chloride, nitrogen, ammonia, etc.) from the hydrogen and epitaxial growth gas inlet 10 into the epitaxial growth region 23 and flowing toward the gas outlet 14, during which the mixed gas of hydrogen and epitaxial growth gas flows from the bottom of the substrate 31 along the polished front surface 46 of the substrate 31, and when a silicon carbide epitaxial layer of a set thickness grows on the polished front surface 46 of the substrate 31, the introduction of the epitaxial growth gas is stopped to end the epitaxial growth process; 8) reducing the temperature of the epitaxial growth zone 23 to 850-950°C at a set rate (5-100°C / min) and maintaining the temperature; 9) The rotation speed of the rotating shaft 25 is reduced to zero, and the base 42 is lowered to the sheet loading and unloading position, and the sheet loading and unloading direction of the base 42 is aligned with the sheet loading and unloading direction of the sheet loading and unloading robot 6; 10) The manipulator 6 in the transfer chamber sequentially transports the carrier ring 35 and the epitaxial wafer thereon to the cooling chamber 1 and places them on the wafer holder 2 for cooling. After the epitaxial wafer is cooled, the manipulator 6 in the transfer chamber 5 transfers it to the wafer holder 1 4 of the wafer loading chamber 3 and then takes it out; 11) Repeat steps 1) to 10) to start processing the next batch of epitaxial wafers.

[0072] When the epitaxial growth chamber for silicon carbide substrate of the present invention is not provided with a carrying ring 35, the operation method for growing an epitaxial layer on a silicon carbide substrate sheet does not have the step of loading and unloading the substrate sheet on the carrying ring. When loading the sheet, the substrate sheet 31 is directly installed in the integrated substrate sheet installation hole 49 of the base 42 by the robot 6, with the polished front side 46 facing downward, and the polished front side 46 of the substrate sheet 31 does not contact other objects. After the epitaxial growth process is completed, the substrate sheet 31 is directly taken out from the integrated substrate sheet installation hole 49 by the robot 6 and sent to the special fixture of the sheet holder 2 2 of the cooling chamber 1, and after cooling, it is sent to the special fixture of the sheet holder 1 4 of the sheet loading chamber 3 by the robot 6 and then taken out.

[0073] The epitaxial growth chamber for silicon carbide substrates described in the present invention can also be used to grow silicon carbide or gallium nitride epitaxial layers on sapphire polished substrates, and can also be used to grow epitaxial layers on substrates of other materials.

[0074] By using the epitaxial growth chamber for silicon carbide substrate of the present invention, when growing silicon carbide or gallium nitride epitaxial layer on silicon carbide substrate, there is no problem of particles falling onto the growing epitaxial layer, and there is no need to rotate the substrate at high speed during the epitaxial growth process to remove the fallen particles, thereby improving the rotation stability of the substrate during the epitaxial process. The problem of easy generation of inclusion defects during the production process of silicon carbide epitaxial wafers is effectively solved, and the goal of achieving a 100% yield of epitaxial wafers without inclusion defects is achieved, and the resistivity and thickness uniformity of the epitaxial wafers are improved by 20%.

[0075] The technical features of the above-described embodiments can be further combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention is given by the attached claims and any equivalent technical solutions thereof.

Claims

1. An epitaxial growth chamber for a silicon carbide substrate, characterized in that: The growth chamber (15) is divided into an upper furnace body (20) and a lower furnace body (17) from top to bottom; at least one heater is provided in the upper furnace body (20) and / or the lower furnace body (17); the outer wall of the lower furnace body (17) is provided with a hydrogen and epitaxial growth gas inlet (10) and an outlet (14), which are connected to the epitaxial growth area (23); A rotating shaft rotating device (26) is provided below the lower furnace body (17), a rotating shaft (25) is provided above the rotating shaft rotating device (26), and the rotating shaft (25) passes through the lower furnace body (17) upwards; The left side wall of the lower furnace body (17) is provided with a hole and a connecting neck (16) to form a sheet loading and unloading channel (9); the outer end of the connecting neck (16) is provided with a growth chamber flange (8); A base rotating shaft (29) is provided on the top of the rotating shaft (25), and a base (42) is provided on the top of the base rotating shaft (29); a bearing ring mounting hole (41) is provided on the base (42) for placing a bearing ring (35), and the bearing ring (35) is used to place a substrate sheet (31) with a polished front side (46) facing downward; The lower furnace body (17) is provided with upper wall plates (48), isolation plates (50), and a lower wall plate (11) from top to bottom; the base (42) and the upper wall plate (32) enclose a loading chamber (43); the loading chamber (43) is connected to the sheet loading and unloading passage (9) and is at the same height; an epitaxial growth zone (23) is enclosed between the isolation plate (18), the base (42), and the lower wall plate (11); the isolation plate (18) and the base (42) separate the sheet loading and unloading passage (9) from the epitaxial growth zone (23); the sheet loading and unloading passage (9) is above the epitaxial growth zone (23).

2. An epitaxial growth chamber for a silicon carbide substrate, characterized in that: The growth chamber (15) is divided into an upper furnace body (20) and a lower furnace body (17) from top to bottom; at least one heater is provided in the upper furnace body (20) and / or the lower furnace body (17); the outer wall of the lower furnace body (17) is provided with a hydrogen and epitaxial growth gas inlet (10) and an outlet (14), which are connected to the epitaxial growth area (23); A rotating shaft rotating device (26) is provided below the lower furnace body (17), a rotating shaft (25) is provided above the rotating shaft rotating device (26), and the rotating shaft (25) passes through the lower furnace body (17) upwards; The left side wall of the lower furnace body (17) is provided with a hole and a connecting neck (16) to form a sheet loading and unloading channel (9); the outer end of the connecting neck (16) is provided with a growth chamber flange (8); A base rotating shaft (29) is provided on the top of the rotating shaft (25), and a base (42) is provided on the top of the base rotating shaft (29); a bearing ring mounting hole (41) is provided on the base (42) for placing a bearing ring (35), and the bearing ring (35) is used to place a substrate sheet (31) with a polished front side (46) facing downward; The lower furnace body (17) is provided with an isolation plate (18) and a lower wall plate (11) from top to bottom, and an epitaxial growth area (23) is surrounded by the isolation plate (18), the base (42) and the lower wall plate (11); the sheet loading and unloading channel (9) is connected to the epitaxial growth area (23), the sheet loading and unloading channel (9) and the epitaxial growth area (23) are at the same height, and sheets are loaded and unloaded in the epitaxial growth area (23).

3. An epitaxial growth chamber for a silicon carbide substrate according to claim 1 or 2, characterized in that: The inner wall of the upper furnace body (20) is provided with a top insulation layer (22) and an upper insulation tube (21) from top to bottom; the inner wall of the lower furnace body (17) is provided with a bottom insulation layer (40) and a lower insulation tube (36).

4. An epitaxial growth chamber for a silicon carbide substrate according to claim 1 or 2, characterized in that: An upper heater (30) is provided inside the upper furnace body (20), and upper electrodes (24) are symmetrically provided on the upper part of the upper furnace body (20), and the upper electrodes (24) are connected to the upper heater (30).

5. An epitaxial growth chamber for growing an epitaxial layer on a silicon carbide substrate according to claim 1 or 2, characterized in that: A lower heater (19) is provided inside the lower furnace body (17) and is located below the lower wall plate (11). A lower electrode (38) is provided at the bottom of the lower furnace body (17), and the lower electrode (38) is connected to the lower heater (19). The base rotating shaft (29) passes through the lower heater (19) upward.

6. An epitaxial growth chamber for a silicon carbide substrate according to claim 1 or 2, characterized in that: The base (42) is provided with 2 to 20 bearing ring mounting holes (41), and the bearing ring mounting holes (41) are evenly distributed on the base (42).

7. An epitaxial growth chamber for a silicon carbide substrate according to claim 1 or 2, characterized in that: The outer wall of the lower furnace body (17) is provided with a hydrogen and epitaxial growth gas inlet (10) and a gas outlet (14); the hydrogen and epitaxial growth gas inlet (10) is connected to an external gas distribution cabinet; and the gas outlet (14) is connected to an external vacuum pump.

8. The epitaxial growth chamber for a silicon carbide substrate according to claim 6, characterized in that: The carrying ring (35) is provided with an inner bevel (47), which contacts only the chamfered surface (45) at the front edge of the substrate sheet (31) and is used to place the substrate sheet (31) with the polished front side (46) facing downward.

9. The epitaxial growth chamber for a silicon carbide substrate according to claim 6, characterized in that: The epitaxial furnace is not provided with a carrying ring (35), the carrying ring mounting hole (41) of the base (42) is changed into an integrated substrate sheet mounting hole (49), and the substrate sheet (31) is directly mounted in the integrated substrate sheet mounting hole (49) of the base (42) by a sheet loading robot (6), with the polished front side (46) facing downward.

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