P-type SiC substrate with low stress and high flatness and regulating device

Abstract

The application discloses a low-stress and high-flatness P-type SiC substrate and a regulating device, and belongs to the technical field of SiC substrate preparation. Warp of a C face and a Si face of the P-type SiC substrate is less than or equal to 100 microns, and Bow of the C face and the Si face of the P-type SiC substrate is less than or equal to 60 microns; a peak value of a largest Raman characteristic peak in the Si face of the P-type SiC substrate is A1, a peak value of a smallest Raman characteristic peak in the Si face of the SiC substrate is A2, and |A1-A2| is less than or equal to 0.1 cm ‑1 ; a peak value of a largest Raman characteristic peak in the C face of the P-type SiC substrate is B1, a peak value of a smallest Raman characteristic peak in the C face of the P-type SiC substrate is B2, and |B1-B2| is less than or equal to 0.1 cm ‑1 . The flatness and stress distribution of the P-type SiC substrate are more uniform, the stability of the physical properties of the SiC substrate is improved, and the service life of a device is prolonged.

Description

Technical Field

[0001] This application relates to a low-stress, high-flatness P-type SiC substrate and a control device, belonging to the field of SiC substrate preparation technology. Background Technology

[0002] Silicon carbide (SiC) single-crystal substrates are considered high-quality materials for fabricating high-temperature, high-frequency, and high-power semiconductor devices due to their excellent physical properties, such as large bandgap, high resistivity and thermal conductivity, and strong breakdown field. Among them, p-type SiC substrates exhibit higher electron mobility compared to holes and achieve lower on-state voltage drop. Therefore, p-type SiC substrates are a key raw material for fabricating SiC-based n-channel IGBTs, and the IGBT devices fabricated from them offer advantages such as fast switching speed and low power consumption.

[0003] In the fabrication of p-type SiC substrates, Al is an ideal dopant element because it generates a shallow acceptor level in the SiC bandgap. Compared to the PVT method, the liquid-phase method offers advantages such as high pressure and low temperature growth, and Al dopant is less prone to evaporation and loss, making it a preferred method for preparing p-type SiC. However, compared to N-type SiC substrates obtained through nitrogen doping, Al atoms have a larger atomic radius, which increases the difficulty in controlling the stress and surface morphology of p-type SiC substrates when grown with Al doping.

[0004] Existing technologies mostly employ mechanical polishing and chemical polishing to process P-type SiC substrates, reducing surface stress, curvature, and warpage, thereby improving the various properties of the P-type SiC substrate. However, these methods are not only complex but also require processing P-type SiC wafers with a thickness greater than the product to obtain the final product, increasing the consumption of P-type SiC.

[0005] Therefore, there is an urgent need for a P-type SiC substrate with relatively uniform stress distribution, low stress, Warp ≤ 100 μm, and Bow ≤ 60 μm. Summary of the Invention

[0006] To address the aforementioned issues, a low-stress, high-flatness P-type SiC substrate is provided. This P-type SiC substrate has a warp ≤ 100 μm and a bow ≤ 60 μm. Furthermore, the difference between the maximum and minimum Raman characteristic peak shifts on both the C- and Si-planes of this P-type SiC substrate is ≤ 0.1 cm. -1 .

[0007] One aspect of this application provides a low-stress, high-flatness P-type SiC substrate, wherein the warp of both the C-plane and the Si-plane of the P-type SiC substrate is ≤100μm, and the bow of both the C-plane and the Si-plane of the P-type SiC substrate is ≤60μm. The peak value of the largest Raman characteristic peak within the Si plane of the P-type SiC substrate is A1, and the peak value of the smallest Raman characteristic peak within the Si plane of the SiC substrate is A2, where |A1-A2|≤0.1cm. -1 ; The peak value of the largest Raman characteristic peak within the C-plane of the P-type SiC substrate is B1, and the peak value of the smallest Raman characteristic peak within the C-plane of the P-type SiC substrate is B2, where |B1-B2|≤0.1cm. -1 .

[0008] At this value, the P-type SiC substrate has a good surface morphology, low in-plane stress and uniform stress distribution, which reduces the cracking rate of the P-type substrate during processing and enhances the stability of downstream epitaxy and device use.

[0009] Preferably, the warp of both the C-plane and Si-plane of the P-type SiC substrate is ≤60μm, and the bow of both the C-plane and Si-plane of the P-type SiC substrate is ≤30μm.

[0010] More preferably, the warp of both the C-plane and Si-plane of the P-type SiC substrate is ≤30μm, and the bow of both the C-plane and Si-plane of the P-type SiC substrate is ≤10μm.

[0011] Optionally, the peak value of the largest Raman characteristic peak within the Si plane of the P-type SiC substrate is A1, and the peak value of the smallest Raman characteristic peak within the Si plane of the P-type SiC substrate is A2, where |A1-A2|≤0.06cm. -1 .

[0012] Optionally, the peak value of the largest Raman characteristic peak within the C-plane of the P-type SiC substrate is B1, and the peak value of the smallest Raman characteristic peak within the C-plane of the P-type SiC substrate is B2, where |B1-B2|≤0.06cm. -1 .

[0013] Optionally, the P-type SiC substrate has a central region, a first edge region surrounding the central region, and a second edge region surrounding the first edge region. The central region is the area within 1 / 2 of the diameter of the P-type SiC substrate, the first edge region is the area within 1 / 2 to 3 / 4 of the diameter of the P-type SiC substrate, and the remainder is the second edge region. The peak value of the largest Raman characteristic peak in the central region of the C-plane of the P-type SiC substrate is a1, and the peak value of the smallest Raman characteristic peak in the central region of the C-plane of the P-type SiC substrate is a2, where |a1-a2|≤0.02cm. -1 .

[0014] Optionally, the peak value of the largest Raman characteristic peak in the first edge region of the C-plane of the P-type SiC substrate is a3, and the peak value of the smallest Raman characteristic peak in the first edge region of the C-plane of the P-type SiC substrate is a4, where |a3-a4|≤0.02cm -1 .

[0015] Optionally, the peak value of the largest Raman characteristic peak in the second edge region of the C-plane of the P-type SiC substrate is a5, and the peak value of the smallest Raman characteristic peak in the second edge region of the C-plane of the P-type SiC substrate is a6, where |a5-a6|≤0.02cm -1 .

[0016] Optionally, the peak value of the largest Raman characteristic peak in the central region of the Si surface of the P-type SiC substrate is b1, and the peak value of the smallest Raman characteristic peak in the central region of the Si surface of the P-type SiC substrate is b2, where |b1-b2|≤0.02cm -1 .

[0017] Optionally, the peak value of the largest Raman characteristic peak in the first edge region of the Si surface of the P-type SiC substrate is b3, and the peak value of the smallest Raman characteristic peak in the first edge region of the Si surface of the P-type SiC substrate is b4, where |b3-b4|≤0.02cm -1 .

[0018] Optionally, the peak value of the largest Raman characteristic peak in the second edge region of the Si surface of the P-type SiC substrate is b5, and the peak value of the smallest Raman characteristic peak in the second edge region of the Si surface of the P-type SiC substrate is b6, where |b5-b6|≤0.02cm -1 .

[0019] Optionally, the shift of the Raman characteristic peak position in the central region of the p-type SiC substrate is C1 cm. -1 0.002≤C1≤0.02, the shift of the Raman characteristic peak position in the first edge region of the P-type SiC substrate is C2cm. -1 0.002≤C2≤0.03, the shift of the Raman characteristic peak position in the second edge region of the p-type SiC substrate is C3 cm. -1 , 0.002≤C3≤0.06.

[0020] Optionally, the crystal form of the P-type SiC substrate is selected from 4H, 6H, and 3C.

[0021] Preferably, the crystal form of the P-type SiC substrate is 4H.

[0022] Optionally, the size of the P-type SiC substrate is ≥2 inches.

[0023] Preferably, the size of the P-type SiC substrate is selected from one of 2 inches, 4 inches, 6 inches, 8 inches, 10 inches, and 12 inches; more preferably, the size of the P-type SiC substrate is selected from one of 4 inches, 6 inches, and 8 inches.

[0024] Optionally, a method for preparing a low-stress, high-flatness P-type SiC substrate includes the following steps: S1: After cutting, grinding and mechanically polishing the P-type SiC substrate, perform initial surface morphology testing to detect the Warp value and Bow value of the Si and C surfaces, as well as the TTV value of the silicon carbide substrate. S2: Based on the P-type SiC substrates with an absolute Bow value of 110-130μm on the C-side or Si-side, the P-type SiC substrates are divided into the first group, and the absolute Bow value of the mold control disk corresponding to the P-type SiC substrates in the first group is determined to be 30±2.5μm. Based on the P-type SiC substrates with an absolute Bow value of 90-110μm, the P-type SiC substrates are divided into the second group, and the absolute Bow value of the mold control disk corresponding to the P-type SiC substrates in the second group is determined to be 15±2.5μm. Based on the P-type SiC substrates with an absolute Bow value of 60-90μm, the P-type SiC substrates are divided into the third group, and the absolute Bow value of the mold control disk corresponding to the P-type SiC substrates in the third group is determined to be 5±2.5μm. S3: Install the mold control plate determined in step S2 onto the pressure plate, then place the P-type SiC substrate into the heat conduction groove, and drive the pressure plate downward through the pressure assembly to achieve the bonding of the mold control plate with the P-type SiC substrate in the heat conduction groove. S4: The P-type SiC substrate is heated once from room temperature to 1400-1600℃. During the heating, pressure is applied once. Then the P-type SiC substrate is heated a second time to 1700-2050℃. During the heating process, pressure is applied a second time to deform the P-type SiC substrate to achieve surface shape control. Then it is rapidly cooled. S5: Perform stress and surface morphology tests on the P-type SiC substrate after surface shape adjustment in step S4 to determine whether the warp of the Si and C surfaces of the P-type SiC substrate is less than 100 μm and the absolute bow value is less than 60 μm. If so, the surface shape adjustment is successful. After polishing, the low-stress, high-flatness P-type SiC substrate is obtained. If not, steps S2-S4 need to be repeated on the adjusted P-type SiC substrate until the warp of the Si and C surfaces of the P-type SiC substrate is less than 100 μm and the absolute bow value is less than 60 μm.

[0025] Specifically, the polishing process in step S5 is only to remove impurities from the P-type SiC substrate and improve the surface smoothness of the P-type SiC substrate, and will not cause significant changes to the surface data of the P-type SiC substrate.

[0026] Specifically, the type of polishing treatment in step S5 is not specifically limited, and those skilled in the art can choose according to their needs.

[0027] Optionally, the pressure applied during the initial pressurization is 30-70 g / cm³. 2 The pressure application time is 5-10 hours.

[0028] Optionally, the pressure of the secondary pressurization is 20-40 g / cm³. 2 The pressure application time is 2-8 hours.

[0029] Optionally, the heating rate of the first heating is 240-400℃ / h, the heating time is 4-6h, and the holding time is 1-2h; the heating rate of the second heating is 60-200℃ / h, the heating time is 3-5h, and the holding time is 2-3h.

[0030] Optionally, the rapid cooling time is 3-6 hours, and the cooling rate is 300-650℃ / h.

[0031] Another aspect of this application provides a P-type SiC substrate surface profile and stress control device, comprising: A fixed column, wherein the interior of the fixed column is hollow and has several first cooling channels; A pressure plate and a tray are provided. The pressure plate is sleeved on the fixed column. The pressure plate has a hollow interior with a second cooling channel. The pressure plate is slidably connected to the fixed column. A pressure assembly is provided on the pressure plate for pressurizing the pressure plate. Several control mold plates are provided on the bottom surface of the pressure plate. The tray is located at the bottom end of the fixed column. Several heat conduction grooves are provided on the upper surface of the tray. The heat conduction grooves are corresponding to the control mold plates. Heating element, the heating element being used to heat a P-type SiC substrate; A numerical control display is disposed at the top of the fixed column. The numerical control display is electrically connected to the pressurizing component and the heating component. The numerical control display is used for displaying and inputting pressure and temperature parameters.

[0032] Optionally, the pressurizing assembly includes a fixing plate, a pressure applying element, and a pressure sensor. The fixing plate is disposed below the CNC display. One end of the fixing plate is fixedly connected to the fixing column. The lower surface of the fixing plate is fixedly connected to one end of the pressure applying element. The other end of the pressure applying element is fixedly connected to the upper surface of the pressurizing plate. The pressure sensor is disposed on the lower surface of the pressurizing plate and is electrically connected to the CNC display.

[0033] Optionally, the pressure-applying component is selected from a cylinder or a telescopic rod.

[0034] Specifically, the type of pressure-applying component is not limited; it can be a cylinder or a telescopic rod, as long as it can apply the corresponding pressure to the pressure plate.

[0035] The beneficial effects of this application include, but are not limited to: 1. The low-stress, high-flatness P-type SiC substrate of this application has uniform stress distribution on the C-plane and Si-plane of the P-type SiC substrate, avoiding stress concentration. In actual use, it reduces the porosity of the bonding interface and improves the performance of the product device.

[0036] 2. According to the preparation method of low-stress, high-flatness P-type SiC substrate of this application, precise control is performed on P-type SiC with different surface features and stress distributions to make the stress and surface features of P-type SiC substrates obtained in mass production uniform and consistent, thereby improving the quality of P-type SiC substrates.

[0037] 3. According to the SiC substrate surface shape and stress control device of this application, through intelligent program setting, based on the surface shape detection results, targeted adjustments and control are made to P-type SiC substrates with different surface shape data, thereby increasing the accuracy of control. Attached Figure Description

[0038] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the P-type SiC substrate surface and stress control device involved in the embodiments of this application; Figure 2 This is a perspective view of the tray involved in the embodiments of this application; Figure 3This is a three-dimensional schematic diagram of the pressure plate involved in the embodiments of this application; Figure 4 This is a cross-sectional schematic diagram of the three-dimensional column involved in the embodiments of this application.

[0039] List of components and reference numerals: 10. Fixed column; 11. First cooling channel; 20. Pressure plate; 21. Second cooling channel; 22. Adjustment mold plate; 30. Tray; 31. Heat conduction groove; 40. CNC display; 50. Heating element; 61. Fixed plate; 62. Pressure application element; 63. Pressure sensor. Detailed Implementation

[0040] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0041] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0042] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0043] The cutting, grinding, or MP processes used in this application are all commonly used techniques in the field, and those skilled in the art can choose according to the actual situation.

[0044] The chemical etching method mentioned in Embodiment 2 of this application is a commonly used silicon carbide substrate processing process in the art, and can be adjusted using commonly used data in the art.

[0045] Example 1 This embodiment provides a SiC substrate surface shape and stress control device, including: a fixed post 10, the fixed post 10 having a hollow interior with a plurality of first cooling channels 11; a pressure plate 20 and a tray 30, the pressure plate 20 being sleeved on the fixed post 10, the pressure plate 20 having a hollow interior with a second cooling channel 21, and the pressure plate 20 being sleeved on the fixed post 10 and moving up and down along the fixed post 10; a plurality of control mold plates 22 being provided on the pressure plate 20, and a pressure assembly being provided on the control mold plates 22, the pressure assembly being used to pressurize the control mold plates 22. The pressurization assembly includes a tray 30 located at the bottom of the fixed column 10, with several heat-conducting grooves 31 on the tray 30, corresponding to the control mold plate 22; a heating element 50 located inside or below the tray 30, used to heat the P-type SiC substrate; and a numerical control display 40 located at the top of the fixed column 10, electrically connected to the pressurization assembly and the heating element 50, used to display and input settings of pressure and temperature parameters.

[0046] This application first performs surface and stress detection on the P-type SiC substrate using an external surface detection device. Then, based on the Bow value of the P-type SiC substrate, a corresponding mold control plate is selected and installed below the pressure plate 20. Next, the P-type SiC substrate is placed in the tray 30. The pressure plate 20 is moved closer to the tray 30 by driving the pressure assembly, thus stably fixing the P-type SiC substrate between the pressure plate 20 and the tray 30. Then, the temperature and heating rate for the first heating stage are set via the CNC display 40. The heating element 50 is controlled to perform the first heating stage. During the heating process, the pressure assembly is controlled to gradually apply pressure to the substrate. The final pressure value and heating time are set. After reaching a certain processing temperature and pressure, this is maintained for a period of time to allow the P-type SiC substrate to be in an elastic deformation state. Finally, the temperature and heating rate for the second heating stage are set via the display, and the heating element 50 is controlled... The temperature is raised again, and a second pressurization is applied during the second heating process. By setting the pressure value and pressure adjustment time for the second pressurization, the driving pressure component is controlled to apply the second pressurization. Then, at the set temperature and pressure value, the pressure is maintained for a certain period of time to adjust the surface shape of the P-type SiC substrate. This causes the P-type SiC substrate to undergo plastic deformation at this temperature, making the deformation stable. Then, a cooling medium is introduced into the first cooling channel 11 and the second cooling channel 21 through an external cooling mechanism to achieve rapid cooling. After cooling is completed, the pressure is released, and the driving pressurization component drives the pressurization plate 20 to rise. Then, the processed P-type SiC substrate is taken out and re-inspected by an external surface shape detection device to see if it meets the surface shape standard. The P-type SiC substrate that meets the surface shape standard is then subjected to simple polishing to obtain a low-stress, high-flatness P-type SiC substrate.

[0047] Specifically, the first cooling channel 11 and the second cooling channel 21 are connected to an external cooling mechanism, which can be an industrial water chiller, an industrial oil chiller, or an air cooler. Those skilled in the art can choose according to their needs.

[0048] Specifically, the type of cooling medium in the first cooling channel 11 and the second cooling channel 21 is not specifically limited. It can be water, oily substances, or gas, as long as it can achieve rapid cooling of the P-type SiC substrate.

[0049] Specifically, this application does not impose any specific limitations on the heating element 50. It can be an electric heating plate, an electric heating coil, or a heating wire, as long as it can achieve the heating of the P-type SiC substrate.

[0050] Specifically, the heating element 50 can be disposed inside the tray 30 or below the tray. When disposed inside the tray 30, the tray 30 is hollow, and the heating element 50 is placed inside. The heating element 50 heats the tray through an external power source. When disposed below the tray 30, a heating shell can be provided, and the heating element 50 is placed in the heating shell. The heating element 50 is heated through the heat conduction between the heating shell and the tray 30. In this case, the heating shell and the tray 30 are preferably made of materials that conduct heat easily. The specific materials can be selected by those skilled in the art as needed.

[0051] As one embodiment, it also includes a thermally conductive powder, which is at least one of carbon powder, graphene, alumina, or nanofluid.

[0052] This setting enables more uniform heating of the P-type SiC substrate, reducing damage to the P-type SiC substrate during elastic and plastic deformation, improving the deformation uniformity of the P-type SiC substrate, reducing the stress of the P-type SiC substrate, and improving the flatness of the P-type SiC substrate.

[0053] In one embodiment, the pressurizing assembly includes a fixing plate 61, a pressure applying element 62, and a pressure sensor 63. The fixing plate 61 is disposed below the CNC display 40. One end of the fixing plate 61 is fixedly connected to the fixing column 10. The lower surface of the fixing plate 61 is fixedly connected to one end of the pressure applying element 62. The other end of the pressure applying element 62 is fixedly connected to the upper surface of the pressurizing plate 20. The pressure sensor 63 is disposed on the lower surface of the pressurizing plate 20 and is electrically connected to the CNC display 40.

[0054] In one embodiment, the pressure-applying component 62 is selected from a cylinder or a telescopic rod.

[0055] Specifically, the type of pressure-applying component 62 is not specifically limited. It can be a cylinder or a telescopic rod. The telescopic rod includes, but is not limited to, an electric telescopic rod, as long as it can apply the corresponding pressure to the pressure plate 20.

[0056] Specifically, the pressure sensor 63 and the mold control plate are spaced apart to avoid conflict, and the pressure sensor 63 and the mold control plate are distributed on the lower surface of the pressure plate 20.

[0057] Example 2 The P-type SiC substrate prepared in this embodiment was fabricated using the P-type SiC substrate surface shape and stress control device of Example 1. Specifically, the chemical etching process in this application is a commonly used technique in the field, and those skilled in the art can use methods commonly used in the prior art to process it.

[0058] SiC substrate #1 The preparation method includes the following steps: S1: After cutting, grinding and mechanically polishing the P-type SiC substrate, its initial surface morphology was tested. The Warp value and Bow value of the Si and C surfaces, as well as the TTV value of the silicon carbide substrate, were detected. The Warp value of the C surface was 94.23 μm, the Warp value of the Si surface was 86.64 μm, and the TTV value was 8.54 μm. S2: Based on the Bow value of the C-side of the P-type SiC substrate in step S1 being 61.40 μm and the Bow value of the Si-side being -69.33 μm, it is determined to be the 3rd group, and the Bow value of the adjustment mold disk 22 is selected to be 5±2.5 μm. S3: Install the control mold disk 22 determined in step S2 onto the pressure disk 20, then place the P-type SiC substrate into the heat conduction groove 31, and drive the pressure disk 20 downward through the pressure assembly to achieve bonding between the control mold disk 22 and the P-type SiC substrate in the heat conduction groove 31. S4: The P-type SiC substrate is heated once at a rate of 240℃ / h for 6 hours, raising the temperature from room temperature to 1440℃. This temperature is then held for 1 hour. Simultaneously, a pressure is applied at a uniform rate to 30 g / cm³. 2 The pressurization time was 6 hours, and the pressure and temperature were maintained for 1 hour. Then, the P-type SiC substrate was heated a second time from 1440℃ to 1700℃ at a heating rate of 60℃ / h for 4.3 hours, and held at this temperature for 3 hours. During the heating process, a second pressurization was performed, increasing the pressure from 30 g / cm³. 2 The average speed decreased to 20g / cm 2 The pressure reduction time was 4.3h, and the pressure and temperature were maintained for 3h to deform the P-type SiC substrate to achieve surface shape control. Then, it was cooled to room temperature at a cooling rate of 300℃ / h for 5.7h. S5: The P-type SiC substrate after surface shape adjustment in step S4 is subjected to stress and surface shape morphology tests. The Warp values ​​of the C-plane and Si-plane of the P-type SiC substrate are determined to be 47.15μm and 46.33μm, respectively, and the Bow values ​​are 38.47μm and -30.63μm, respectively, which proves that the surface shape adjustment of the P-type SiC substrate is successful. After polishing, the low-stress, high-flatness P-type SiC substrate is obtained.

[0059] SiC substrate #2 The preparation method includes the following steps: S1: After cutting, grinding and mechanically polishing the P-type SiC substrate, its initial surface morphology was tested. The Warp value and Bow value of the Si and C surfaces, as well as the TTV value of the silicon carbide substrate, were detected. The Warp value of the C surface was 108.45 μm, the Warp value of the Si surface was 92.36 μm, and the TTV value was 10.21 μm. S2: Based on the Bow value of the C surface of the P-type SiC substrate being 94.77 μm and the Bow value of the Si surface being -90.21 μm in step S1, it is determined to be the second group. The C surface of the P-type SiC substrate is attached to the control mold disk 22, and the Bow value of the control mold disk 22 is selected to be 15±2.5 μm. S3: Install the control mold disk 22 determined in step S2 onto the pressure disk 20, then place the P-type SiC substrate into the heat conduction groove 31, and drive the pressure disk 20 downward through the pressure assembly to achieve bonding between the control mold disk 22 and the P-type SiC substrate in the heat conduction groove 31. S4: The P-type SiC substrate is heated once at a rate of 400℃ / h for 4 hours, raising the temperature from room temperature to 1600℃. This temperature is then held for 2 hours. Simultaneously with the heating, a pressure is applied at a uniform rate for 4 hours, gradually increasing the pressure to 70 g / cm³. 2 The substrate was maintained at this pressure and temperature for 2 hours, followed by a second heating of the P-type SiC substrate from 1600℃ to 2050℃ at a heating rate of 200℃ / h for 2.25 hours. It was then held at this temperature for 2 hours. During this heating process, a second pressurization was applied, increasing the pressure from 70 g / cm³. 2 The average speed decreased to 40g / cm 2 The pressure reduction time was 2.25h, and the pressure and temperature were maintained for 2h to cause deformation of the P-type SiC substrate to achieve surface shape control. Then, it was cooled to room temperature at a cooling rate of 650℃ / h for 3h. S5: The P-type SiC substrate after surface shape adjustment in step S4 is subjected to stress and surface shape morphology tests. The Warp values ​​of the C-plane and Si-plane of the P-type SiC substrate are determined to be 64.37 μm and 60.71 μm, respectively, and the Bow values ​​are 52.48 μm and -49.67 μm, respectively, which proves that the surface shape adjustment of the P-type SiC substrate is successful. After polishing, the low-stress, high-flatness P-type SiC substrate is obtained.

[0060] Comparison of SiC substrate D1# The difference between this comparative SiC substrate and SiC substrate 2# is that step S4 involves only one heating and no second heating; the rest is the same as in Example 3.

[0061] Comparison with SiC substrate D2# The difference between this comparative SiC substrate and SiC substrate 2# is that natural cooling is used in step S4, while the rest is the same as in Example 3.

[0062] Comparison of SiC substrate D3# The difference between this comparative SiC substrate and SiC substrate 2# is that, after cutting, grinding and mechanically polishing the P-type SiC substrate, the surface of the P-type SiC substrate is treated by chemical etching process to obtain the P-type SiC substrate. The rest is the same as in Example 3.

[0063] Test Example 1 The surface profile of the P-type SiC substrate in Example 2 was tested using instruments before and after conditioning. The test results are shown in Tables 1 and 2 below.

[0064] Table 1

[0065] Table 2

[0066] Test Example 2 The p-type SiC substrate obtained in Example 2 after manipulation was characterized using micro-Raman spectroscopy. The shift of the Raman characteristic peak position in the central region of the p-type SiC substrate was determined by C1 = Max|x1- |-Min|x1- | where x1 is the Raman peak position of a single test point in the central region being tested. The average Raman peak position of all test points in the central region of the test; the shift of the Raman characteristic peak position in the first edge region of the P-type SiC substrate, C2 = Max|x2- |-Min|x2- | where x2 is the Raman peak position of a single test point in the first edge region being tested. The average Raman peak position of all test points in the first edge region is given; the shift of the Raman characteristic peak position in the second edge region of the P-type SiC substrate is given by C3 = Max|x3- |-Min|x3- | where x3 is the Raman peak position of a single test point in the second edge region being tested. The average Raman peak value of all test points in the second edge region being tested; Si surface curvature change = |Bow value 处理前 - Bow value 处理后 The test results are shown in Table 3.

[0067] Table 3

[0068] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A low-stress, high-flatness P-type SiC substrate, characterized in that, The warp of both the C-plane and Si-plane of the P-type SiC substrate is ≤100μm, and the bow of both the C-plane and Si-plane of the P-type SiC substrate is ≤60μm. The peak value of the largest Raman characteristic peak within the Si plane of the P-type SiC substrate is A1, and the peak value of the smallest Raman characteristic peak within the Si plane of the SiC substrate is A2, where |A1-A2|≤0.1cm. -1 ; The peak value of the largest Raman characteristic peak within the C-plane of the P-type SiC substrate is B1, and the peak value of the smallest Raman characteristic peak within the C-plane of the P-type SiC substrate is B2, where |B1-B2|≤0.1cm. -1 .

2. The low-stress-distribution, high-flatness P-type SiC substrate according to claim 1, characterized in that, The peak value of the largest Raman characteristic peak within the Si plane of the P-type SiC substrate is A1, and the peak value of the smallest Raman characteristic peak within the Si plane of the P-type SiC substrate is A2, where |A1-A2|≤0.06cm. -1 ; and / or The peak value of the largest Raman characteristic peak within the C-plane of the P-type SiC substrate is B1, and the peak value of the smallest Raman characteristic peak within the C-plane of the P-type SiC substrate is B2, where |B1-B2|≤0.06cm. -1 .

3. The low-stress, high-flatness P-type SiC substrate according to claim 1, characterized in that, The P-type SiC substrate has a central region, a first edge region surrounding the central region, and a second edge region surrounding the first edge region. The central region is the area within 1 / 2 of the diameter of the P-type SiC substrate, the first edge region is the area within 1 / 2 to 3 / 4 of the diameter of the P-type SiC substrate, and the remainder is the second edge region. The peak value of the largest Raman characteristic peak in the central region of the C-plane of the P-type SiC substrate is a1, and the peak value of the smallest Raman characteristic peak in the central region of the C-plane of the P-type SiC substrate is a2, where |a1-a2|≤0.02cm. -1 .

4. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The peak value of the largest Raman characteristic peak in the first edge region of the C-plane of the P-type SiC substrate is a3, and the peak value of the smallest Raman characteristic peak in the first edge region of the C-plane of the P-type SiC substrate is a4, where |a3-a4|≤0.02cm. -1 .

5. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The peak value of the largest Raman characteristic peak in the second edge region of the C-plane of the P-type SiC substrate is a5, and the peak value of the smallest Raman characteristic peak in the second edge region of the C-plane of the P-type SiC substrate is a6, where |a5-a6|≤0.02cm. -1 .

6. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The peak value of the largest Raman characteristic peak in the central region of the Si surface of the P-type SiC substrate is b1, and the peak value of the smallest Raman characteristic peak in the central region of the Si surface of the P-type SiC substrate is b2, where |b1-b2|≤0.02cm. -1 .

7. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The peak value of the largest Raman characteristic peak in the first edge region of the Si surface of the P-type SiC substrate is b3, and the peak value of the smallest Raman characteristic peak in the first edge region of the Si surface of the P-type SiC substrate is b4, where |b3-b4|≤0.02cm. -1 .

8. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The peak value of the largest Raman characteristic peak in the second edge region of the Si surface of the P-type SiC substrate is b5, and the peak value of the smallest Raman characteristic peak in the second edge region of the Si surface of the P-type SiC substrate is b6, where |b5-b6|≤0.02cm. -1 .

9. The low-stress, high-flatness P-type SiC substrate according to claim 3, characterized in that, The shift of the Raman characteristic peak in the central region of the P-type SiC substrate is C1 cm. -1 0.002≤C1≤0.02, the shift of the Raman characteristic peak position in the first edge region of the P-type SiC substrate is C2 cm. -1 0.002≤C2≤0.003, the shift of the Raman characteristic peak position in the second edge region of the p-type SiC substrate is C3 cm. -1 , 0.002≤C3≤0.

006.

10. A p-type SiC substrate surface profile and stress control device, characterized in that, include: A fixed column, wherein the interior of the fixed column is hollow and has several first cooling channels; A pressure plate and a tray are provided. The pressure plate is sleeved on the fixed column. The pressure plate has a hollow interior with a second cooling channel. The pressure plate is sleeved on the fixed column and moves up and down along the fixed column. The pressure plate is provided with a plurality of control mold plates. The control mold plates are provided with pressure components. The pressure components are used to pressurize the control mold plates. The tray is located at the bottom end of the fixed column. The tray is provided with a plurality of heat conduction grooves. The heat conduction grooves are corresponding to the control mold plates. A heating element, which is disposed inside the tray or below the tray, is used to heat a P-type SiC substrate; A numerical control display is disposed at the top of the fixed column. The numerical control display is electrically connected to the pressurizing component and the heating component. The numerical control display is used for displaying and inputting pressure and temperature parameters.

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