Silicon carbide epitaxial wafer growth carrying disc
By designing an insulating ring and graphite ring in the growth loading plate of the silicon carbide epitaxial sheet, it isolates solid heat transfer and uses gas heat transfer and heat radiation to solve the problem of substrate thermal field unevenness and improves the concentration of the silicon carbide epitaxial sheet. and device quality.
Patent Information
- Application Number
- CN202420642554.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-29
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2034-03-29
AI Technical Summary
There is a gap between the existing silicon carbide epitaxial sheet growth carrier substrate and the carrier disk, resulting in uneven thermal field of the substrate and affecting the concentration uniformity of the epitaxial sheet.
A silicon carbide epitaxial plate growth carrier disk including a main body carrier disk, an insulating ring and a graphite ring is designed. The insulating ring has an annular support portion, the support portion is placed on the inner ring convex ring, and the graphite ring is arranged on the edge of the carrier disk. By isolating the solid heat transfer pathway, gas heat transfer and thermal radiation are used as epitaxial heat sources to ensure uniform temperature field.
By isolating solid heat transfer and using gas heat transfer and thermal radiation as epitaxial heat sources, the concentration uniformity of the silicon carbide epitaxial sheet is significantly improved and the quality of the device is improved.
Smart Images
Figure CN222119470U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductors, in particular to a silicon carbide epitaxial wafer growth carrier capable of improving concentration uniformity. Background Art
[0002] Silicon carbide (SiC) is widely used in power semiconductor devices due to its excellent physical properties and has extremely high application value. SiC devices currently on the market are made by homoepitaxially growing a SiC layer on a SiC substrate and then manufacturing the device on the epitaxial layer. Compared with directly manufacturing devices on a SiC substrate, through homoepitaxial growth, silicon carbide layers of different doping types can be obtained in the vertical direction, which can reduce the requirements for ion implantation in the device manufacturing process and make it easier to meet the needs of device design.
[0003] SiC homoepitaxial growth is usually carried out by chemical vapor deposition (CVD). The main specifications of homogeneous SiC epitaxial wafers are defect density, doping concentration and epitaxial thickness. Among them, the uniformity of doping concentration has a huge impact on the electrical performance of the device, so the uniformity within the wafer is crucial.
[0004] One factor that affects the uniformity within the wafer is the SiC epitaxial wafer growth carrier. The substrate and carrier of the existing SiC epitaxial wafer growth carrier cannot be completely in contact, and there is a gap between the substrate and the carrier. During epitaxial growth, there are three conditions for heat transfer on the back of the substrate: thermal radiation, gas-solid heat conduction, and heat conduction between solids. The main heat source required for substrate epitaxy is thermal radiation, but the existence of gas-solid heat conduction and heat conduction between solids on the back of the substrate will lead to slight differences in the thermal field of the substrate, which is ultimately reflected in the poor concentration uniformity within the epitaxial wafer.
[0005] Therefore, it is necessary to provide a silicon carbide epitaxial wafer growth carrier that can improve the concentration uniformity within the silicon carbide epitaxial wafer to solve the above problems. Utility Model Content
[0006] The utility model aims to provide a silicon carbide epitaxial wafer growth carrier capable of improving the concentration uniformity within the silicon carbide epitaxial wafer.
[0007] To achieve the above-mentioned purpose, the technical solution of the utility model is: to provide a silicon carbide epitaxial wafer growth carrier, which includes a main carrier, an insulating ring and a graphite ring; an inner ring convex ring is convexly provided in the middle of the main carrier; the insulating ring has a circular ring-shaped support portion, the outer diameter of the support portion is the same as the outer diameter of the inner ring convex ring, and the support portion is placed above the inner ring convex ring; the graphite ring is arranged at the edge of the main carrier, and the top of the graphite ring is higher than the top of the support portion.
[0008] Preferably, the insulating ring also includes an abutment portion arranged perpendicular to the supporting portion, and the abutment portion is sleeved in the inner ring convex ring and abuts against the inner wall thereof. Such a structural arrangement, on the one hand, fixes the insulating ring in the inner ring convex ring to avoid large displacement of the insulating ring due to the centrifugal force generated when the carrier plate rotates; on the other hand, when the substrate is placed on the insulating ring, the insulating ring is hidden under the substrate to avoid silicon carbide deposition on the insulating ring due to the gap between the substrate and the graphite ring.
[0009] Preferably, the thickness of the support portion is greater than or equal to 0.3 mm, so that the support portion is at least 0.3 mm higher than the outer ring convex ring, so that the deposited SiC will only be deposited in the outer ring convex ring and the annular groove between it and the inner ring convex ring, and will not be deposited on the support portion.
[0010] Preferably, the insulation ring is a porous structure, and the insulation ring is made of porous graphite such as graphite felt, so it has a certain degree of softness, can be more adaptive to the substrate under the action of airflow, and has universal applicability.
[0011] Preferably, the insulation ring has a certain flexibility, so it can be more adaptive to the substrate under the action of airflow and has universal applicability.
[0012] Preferably, an outer convex ring is convexly provided at the edge of the main body carrier, the height of the outer convex ring is lower than the top of the support part, and the graphite ring is sleeved outside the outer convex ring and higher than the top of the outer convex ring. The outer convex ring is provided to make it easier for operators to take and place epitaxial wafers, and the height of the outer convex ring is set to be lower than the top of the support part, so that when the gap between the substrate and the graphite ring causes silicon carbide deposition, the deposited SiC will only be deposited on the outer convex ring and in the annular groove between it and the inner convex ring, and will not be deposited on the insulation ring, thereby avoiding the friction between the deposited SiC and the substrate during the next epitaxy to produce unnecessary particles.
[0013] Preferably, the height of the outer ring convex ring is the same as that of the inner ring convex ring, and an annular groove is formed therebetween. Since there is an irregular growth gap between the substrate and the graphite ring, the outer ring convex ring is arranged so that its top is lower than the support portion, so that SiC deposited through the aforementioned growth gap will only be deposited in the outer ring convex ring and the annular groove, and will not be deposited on the insulation ring.
[0014] Preferably, the outer ring convex ring has a vertical wall, the outer ring convex ring is concentrically arranged with the inner ring convex ring, and the vertical wall is tangent to the inner ring convex ring. Therefore, the support portion provided on the inner ring convex ring is located within the shortest radius of the main positioning edge. After placing the substrate, the entire insulation ring is located under the substrate to reduce contact with the carrier gas.
[0015] Preferably, the inner wall shape of the graphite ring corresponds to the outer wall shape of the outer convex ring, so as to achieve the positioning of the graphite ring and avoid large displacement of the graphite ring due to the centrifugal force generated when the carrier plate rotates.
[0016] Preferably, an outer wall of the main body carrier is provided with a mounting portion protruding along its radial direction, and the graphite ring is mounted on the mounting portion.
[0017] Compared with the prior art, the silicon carbide epitaxial wafer growth carrier of the utility model is provided with an insulating ring, the insulating ring has a supporting portion in the shape of an annular ring, and an inner convex ring is correspondingly arranged in the middle of the main carrier, the outer diameter of the inner convex ring is the same as the outer diameter of the supporting portion, and the supporting portion is placed above the inner convex ring. During epitaxial growth, the substrate is placed on the supporting portion of the insulating ring, and the insulating ring is used as the back side isolation of the substrate to isolate the direct contact between the silicon carbide substrate and the main carrier, and the upper half of the heat radiation and the magnetocaloric effect of the substrate under the changing magnetic field are used as the epitaxial heat source, that is, the present application adopts the method of isolating the solid heat transfer path, and only uses gas heat transfer and heat radiation as the epitaxial heat source for epitaxy, so as to obtain a more uniform temperature field, so that the epitaxial wafer has better concentration uniformity, and improves the quality of the silicon carbide epitaxial wafer. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a top view of the silicon carbide epitaxial wafer growth carrier of the present invention.
[0019] Figure 2 yes Figure 1 sectional view of .
[0020] Figure 3 yes Figure 1 Schematic diagram of the structure of the middle insulation ring.
[0021] Figure 4 yes Figure 3 Schematic diagram of the structure from another angle.
[0022] Figure 5 It is a cross-sectional view of a silicon carbide epitaxial wafer growth carrier of the utility model for placing a substrate. DETAILED DESCRIPTION
[0023] The embodiments of the present invention are now described with reference to the accompanying drawings, in which similar element numbers represent similar elements. It should be noted that the orientation descriptions involved in the present invention, such as the orientations or positional relationships indicated by up, down, left, right, front, and back, are all based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present application or / and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The first, second, etc. described are only used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0024] Combination Figure 1-Figure 5 As shown, the silicon carbide epitaxial wafer growth carrier 100 provided by the utility model comprises a main carrier 110, an insulating ring 120 and a graphite ring 130. The insulating ring 120 has a support portion 121 in a circular ring shape. An inner ring convex ring 111 is convexly arranged in the middle of the main carrier 110, and the outer diameter of the inner ring convex ring 111 is the same as the outer diameter of the support portion 121, and the support portion 121 is placed above the inner ring convex ring 111. The graphite ring 130 is arranged at the edge of the main carrier 110, and the top of the graphite ring 130 is higher than the top of the insulating ring 120. Therefore, the graphite ring 130 encloses a placement area for the substrate 200, and the substrate 200 is placed on the support portion 121 for epitaxial growth. The support portion 121 prevents the substrate 200 from directly contacting the main carrier 110, thereby isolating the solid heat transfer path, and only uses gas heat transfer and thermal radiation as epitaxial heat sources for epitaxy, thereby obtaining a more uniform temperature field and making the epitaxial wafer have better concentration uniformity.
[0025] Continue to view Figure 1 As shown, in a specific embodiment, the inner ring 111 is set at a radius of 70mm of the main body carrier 110. Specifically, the inner ring 111 is concentrically arranged with the main body carrier 110, and the radius R1 of the outer wall of the inner ring 111 is 70mm. Correspondingly, the radius of the outer edge of the support portion 121 is also set to 70mm. In this way, when the support portion 121 is placed on the inner ring 111, its outer edge is flush with the outer wall of the inner ring 111, as shown in FIG. Figure 2 shown.
[0026] Continue to view Figure 1 As shown, in this specific embodiment, the radius R2 of the inner edge of the support portion 121 is 67.5 mm, that is, the width of the support portion 121 is set to 2.5 mm to form a stable support for the substrate 200.
[0027] It is understandable that in other embodiments, the width of the support portion 121 is not limited to the above embodiment. The inner diameter, outer diameter and width of the support portion 121 can be flexibly set according to the size of the main carrier 110 and the needs of epitaxial growth, and the width of the inner ring 111 can be adjusted accordingly.
[0028] Combine the following Figure 2-Figure 5 As shown, in one embodiment of the present invention, the heat insulating ring 120 further includes an abutting portion 122 arranged perpendicularly to the supporting portion 121, and the outer diameter of the abutting portion 122 corresponds to the inner diameter of the inner ring convex ring 111. After installation, the abutting portion 122 is sleeved in the inner ring convex ring 111 and abuts against its inner wall, and the supporting portion 121 is placed above the inner ring convex ring 111, as shown in FIG. Figure 2 The structure of the insulating ring 120, on the one hand, fixes the insulating ring 120 in the inner convex ring 111 to prevent the insulating ring 120 from being greatly displaced due to the centrifugal force generated when the carrier 100 rotates; on the other hand, when the substrate 200 is placed on the insulating ring 120, the insulating ring 120 is hidden under the substrate 200 to prevent silicon carbide deposition on the insulating ring 120 due to the gap between the substrate 200 and the graphite ring 130.
[0029] Continue to combine Figure 2 , Figure 5 As shown, the thickness H of the support portion 121 is preferably greater than or equal to 0.3 mm, so that the support portion 121 is at least 0.3 mm higher than the outer ring convex ring 112 (described later). In a specific embodiment, the thickness H of the support portion 121 is set to 0.3 mm, so that the top of the support portion 121 is 0.3 mm higher than the top of the outer ring convex ring 112. During the epitaxial growth process, SiC deposited through the gap between the graphite ring 130 and the substrate 200 will only be deposited in the outer ring convex ring 112 and the annular groove 113 between it and the inner ring convex ring 111, and will not be deposited on the support portion 121.
[0030] More preferably, the insulating ring 120 is a porous structure, and the insulating ring 120 is preferably made of porous graphite such as graphite felt, so it has a certain degree of softness, and can be more adaptive to the substrate 200 under the action of the airflow, and has universal applicability. In addition, the thermal conductivity of the insulating ring 120 is 0.035-0.055W / (m·K), and the solid heat transfer path is isolated by the insulating ring 120. Of course, the insulating ring 120 is not limited to the aforementioned materials, and can also be made of other materials that can make it have a certain degree of flexibility.
[0031] Continue to combine Figure 1-Figure 5As shown, in the present invention, an outer ring convex ring 112 is convexly provided at the edge of the main body carrier 110, and the outer ring convex ring 112 is concentrically arranged with the inner ring convex ring 111, and the inner ring convex ring 111 is located within the shortest radius of the main positioning edge of the outer ring convex ring 112, and an annular groove 113 is formed between the inner ring convex ring 111 and the outer ring convex ring 112, as shown in FIG. Figure 1-2 As shown. Moreover, the height of the outer ring convex ring 112 is lower than the top of the support portion 121 of the insulating ring 120. The graphite ring 130 is sleeved outside the outer ring convex ring 112 and fixed relatively thereto, and the top of the graphite ring 130 is higher than the top of the outer ring convex ring 112. The graphite ring 130 surrounds an epitaxial growth area. In the utility model, the outer ring convex ring 112 is provided to make it easier for operators to take and place epitaxial wafers, and the height of the outer ring convex ring 112 is set to be lower than the top of the insulating ring 120, so that when the gap between the substrate 200 and the graphite ring 130 causes silicon carbide to be deposited, the deposited SiC will only be deposited on the outer ring convex ring 112 and in the annular groove 113 between it and the inner ring convex ring 111, and will not be deposited on the insulating ring 120, thereby avoiding the friction between the deposited SiC and the substrate 200 during the next epitaxy to produce unnecessary particles.
[0032] See also Figure 1-2 As shown, in one embodiment of the utility model, the height of the outer ring convex ring 112 is the same as the height of the inner ring convex ring 111, and an annular groove 113 is formed between the outer ring convex ring 112 and the inner ring convex ring 111. In addition, the outer ring convex ring 112 includes a vertical wall 112a and an arc-shaped wall 112b, and the vertical wall 112a intersects with the arc where the arc-shaped wall 112b is located, and the vertical wall 112a forms the main positioning edge of the main carrier 110. In addition, the outer ring convex ring 112 is concentrically arranged with the inner ring convex ring 111, and the vertical wall 112a is tangent to the inner ring convex ring 111, that is, the inner ring convex ring 111 is located within the shortest radius of the main positioning edge of the outer ring convex ring 112. When the insulation ring 120 is installed on the inner ring convex ring 111, the support portion 121 of the insulation ring 120 is located within the shortest radius of the main positioning edge. Combined with Figure 5 As shown, after the substrate 200 is placed, the substrate 200 is supported by the insulating ring 120 without contacting the main carrier 110, thereby isolating the solid heat transfer path. At the same time, the insulating ring 120 is entirely located below the substrate 200 to reduce contact with the carrier gas. The SiC deposited through the irregular growth gap between the substrate 200 and the graphite ring 130 will only be deposited in the outer ring convex ring 112 and the annular groove 113, and will not be deposited on the insulating ring 120.
[0033] See again Figure 1As shown, in the present invention, the inner wall shape of the graphite ring 130 corresponds to the outer wall shape of the outer ring convex ring 112, that is, the inner wall of the graphite ring 130 is also provided with a vertical side wall 131, and the vertical side wall 131 corresponds to the vertical wall 112a of the outer ring convex ring 112. When the graphite ring 130 is installed, the graphite ring 130 is sleeved outside the outer ring convex ring 112, and the vertical side wall 131 of the graphite ring 130 abuts against the vertical wall 112a of the outer ring convex ring 112, so as to realize the positioning of the graphite ring 130, so as to avoid the large displacement of the graphite ring 130 caused by the centrifugal force generated when the carrier plate rotates.
[0034] See again Figure 2 As shown, in the utility model, the outer wall of the main body carrier 110 is provided with a mounting portion 114 along its radial direction, and the mounting portion 114 is protruded approximately in the middle of the height direction of the main body carrier 110, and the shape of the mounting portion 114 corresponds to the projection shape of the graphite ring 130, the graphite ring 130 is installed on the mounting portion 114, and the inner wall of the graphite ring 130 abuts against the outer ring convex ring 112, and the top of the graphite ring 130 is higher than the top of the outer ring convex ring 112.
[0035] Combine again below Figure 1-Figure 5 As shown, the installation and working principle of the silicon carbide epitaxial wafer growth carrier 100 of the present invention are explained.
[0036] Combination Figure 1-Figure 5 As shown, when installing the thermal insulation ring 120, the abutting portion 122 of the thermal insulation ring 120 is sleeved in the inner ring convex ring 111 and abuts against the inner wall thereof, and the supporting portion 121 is placed on the top of the inner ring convex ring 111, thereby achieving the installation of the thermal insulation ring 120. After installation, the supporting portion 121 of the thermal insulation ring 120 is higher than the outer ring convex ring 112, so the supporting portion 121 is used to support the substrate 200 for epitaxial growth.
[0037] Then, the graphite ring 130 is installed outside the outer ring convex ring 112, and the vertical side wall 131 of the graphite ring 130 is in contact with the vertical wall 112a of the outer ring convex ring 112. Figure 1-2 As shown, the graphite ring 130 is positioned to avoid large displacement of the graphite ring 130 due to the centrifugal force generated when the carrier plate rotates.
[0038] See also Figure 5 As shown, during epitaxial growth, the substrate 200 is placed on the support portion 121 of the insulation ring 120, the support portion 121 is completely hidden under the substrate 200, and there is a certain gap between the edge of the substrate 200 and the side wall of the graphite ring 130, and the gap is an irregular growth gap, such as Figure 5As shown. During the epitaxial growth process, SiC deposited through the aforementioned growth gap will only be deposited on the outer ring 112 and the annular groove 113 between it and the inner ring 111, and will not be deposited on the support portion 121. In addition, the insulating ring 120 is used to isolate the back of the substrate 200 so that the substrate 200 is not in direct contact with the main carrier 110. Instead, the upper half of the heat radiation and the magnetocaloric effect of the substrate 200 under a changing magnetic field are used as epitaxial heat sources. Therefore, the insulating ring 120 isolates the solid heat transfer path and only uses gas heat transfer and thermal radiation as epitaxial heat sources for epitaxy, thereby obtaining a more uniform temperature field and making the epitaxial wafer have better concentration uniformity.
[0039] In summary, due to the silicon carbide epitaxial wafer growth carrier 100 of the utility model, an insulating ring 120 is additionally provided, and the insulating ring 120 has a circular ring-shaped support portion 121, and an inner ring convex ring 111 is correspondingly arranged in the middle of the main carrier 110, and the outer diameter of the inner ring convex ring 111 is the same as the outer diameter of the support portion 121, and the support portion 121 is placed above the inner ring convex ring 111. During epitaxial growth, the substrate 200 is placed on the support portion 121 of the insulating ring 120, and the insulating ring 120 is used to isolate the back side of the substrate 200, isolating the direct contact between the silicon carbide substrate 200 and the main carrier 110, and using the upper half of the heat radiation and the magnetocaloric effect of the substrate 200 under a changing magnetic field as the epitaxial heat source, that is, the present application adopts a method of isolating the solid heat transfer path and only uses gas heat transfer and thermal radiation as the epitaxial heat source for epitaxy, thereby obtaining a more uniform temperature field, so that the epitaxial wafer has better concentration uniformity, and the quality of the silicon carbide epitaxial wafer is improved.
[0040] The structures of other parts of the silicon carbide epitaxial wafer growth carrier 100 involved in the present invention are conventional structures well known to ordinary technicians in the field, and will not be described in detail here.
[0041] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.
Claims
1. A silicon carbide epitaxial wafer growth carrier, characterized in that: include: A main body carrier plate, wherein an inner convex ring is convexly provided in the middle of the main body carrier plate; An insulating ring, the insulating ring having a supporting portion in the shape of an annulus, the outer diameter of the supporting portion being the same as the outer diameter of the inner convex ring, and the supporting portion being placed above the inner convex ring; A graphite ring is arranged at the edge of the main body carrier, and the top of the graphite ring is higher than the top of the supporting part.
2. The silicon carbide epitaxial wafer growth carrier according to claim 1, characterized in that: The heat-insulating ring further comprises an abutting portion which is arranged perpendicularly to the supporting portion, and the abutting portion is sleeved in the inner ring convex ring and abuts against the inner wall thereof.
3. The silicon carbide epitaxial wafer growth carrier according to claim 1 or 2, characterized in that: The thickness of the support portion is greater than or equal to 0.3 mm.
4. The silicon carbide epitaxial wafer growth carrier according to claim 1 or 2, characterized in that: The thermal insulation ring is a porous structure.
5. The silicon carbide epitaxial wafer growth carrier according to claim 1 or 2, characterized in that: The thermal insulation ring has certain flexibility.
6. The silicon carbide epitaxial wafer growth carrier according to claim 1 or 2, characterized in that: An outer ring protrudes from the edge of the main body carrier, the height of which is lower than the top of the support portion, and the graphite ring is sleeved outside the outer ring protrusion and is higher than the top of the outer ring protrusion.
7. The silicon carbide epitaxial wafer growth carrier according to claim 6, characterized in that: The height of the outer ring convex ring is the same as the height of the inner ring convex ring.
8. The silicon carbide epitaxial wafer growth carrier according to claim 6, characterized in that: The outer ring convex ring has a vertical wall. The outer ring convex ring is concentrically arranged with the inner ring convex ring, and the vertical wall is tangent to the inner ring convex ring.
9. The silicon carbide epitaxial wafer growth carrier according to claim 8, characterized in that: The inner wall shape of the graphite ring corresponds to the outer wall shape of the outer ring convex ring.
10. The silicon carbide epitaxial wafer growth carrier according to claim 1, characterized in that: The outer wall of the main body carrier is provided with a mounting portion protruding along its radial direction, and the graphite ring is mounted on the mounting portion.