Circular ring and base suitable for thick epitaxial growth of silicon carbide
By using a beveled ring structure during the thick epitaxial growth of silicon carbide, the problem of by-product accumulation is solved, the probability of airflow disturbance and by-product particles is reduced, and the yield of wafers is improved.
Patent Information
- Application Number
- CN202411834051.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-02-07
AI Technical Summary
During the thick epitaxial growth of silicon carbide, by-products accumulate too quickly, affecting gas transportation and by-product particles falling off, reducing the yield of the wafer.
The oblique ring structure is adopted, and by providing annular protrusions on the lower and upper end surfaces of the ring body, the disturbance of by-product accumulation to the airflow and the probability of by-product particles falling off is reduced.
It effectively reduces the disturbance of by-product accumulation on the airflow, reduces the probability of by-product particles falling on the wafer surface, and improves the yield of silicon carbide epitaxial.
Smart Images
Figure CN119392366A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a ring and a base suitable for silicon carbide thick epitaxial growth, belonging to the technical field of semiconductors. Background Art
[0002] Silicon carbide (SiC), as a third-generation semiconductor material, has unique physical and electrical properties compared to silicon. It has the advantages of high breakdown electric field strength, high electron saturation drift rate, high electron mobility, high thermal conductivity, high melting point, strong radiation resistance and good chemical stability. Therefore, it has a very broad application prospect in the manufacture of electronic devices working under extreme conditions such as high temperature, high pressure, high speed, high frequency and strong radiation.
[0003] In the production of silicon carbide epitaxy, the rings used to grow thin epitaxy and the rings used to grow thick epitaxy are universal. However, due to the long growth time and high growth rate of thick epitaxy, the byproducts on the rings accumulate too quickly, especially the outermost ring of the ring will form an extremely high byproduct accumulation layer. The excessively high growth rate also causes these generated byproducts to be very loose, which will affect the gas transportation during the long growth process and the byproduct particles will fall off on the silicon carbide wafer, affecting the subsequent yield. Summary of the invention
[0004] In response to the above technical problems, the present invention provides a ring and a base suitable for thick epitaxial growth of silicon carbide. The ring uses a beveled ring structure, which can reduce the disturbance of airflow caused by excessive accumulation of by-products during growth and reduce the probability of by-product particles falling on the wafer surface.
[0005] To achieve the above object, the present invention adopts the following technical solutions:
[0006] A ring suitable for thick epitaxial growth of silicon carbide, comprising:
[0007] A circular ring body, wherein the lower end surface of the circular ring body is provided with a first circular protrusion extending downward, and the cross-sectional width of the first circular protrusion is smaller than the cross-sectional width of the circular ring body;
[0008] The upper end surface of the circular ring body is provided with a second annular protrusion extending upward; the cross-sectional width of the second annular protrusion is smaller than the cross-sectional width of the circular ring body but larger than the cross-sectional width of the first annular protrusion, the cross-sectional shape of the second annular protrusion is triangular, and the cross-sectional height of the second annular protrusion gradually decreases from one end close to the inner wall surface of the circular ring body to one end of the outer wall surface of the circular ring body.
[0009] A ring suitable for thick epitaxial growth of silicon carbide, comprising:
[0010] A circular ring body, wherein the lower end surface of the circular ring body is provided with a first circular protrusion extending downward, and the cross-sectional width of the first circular protrusion is smaller than the cross-sectional width of the circular ring body;
[0011] The upper end face of the circular ring body is provided with a second annular protrusion extending upward; the cross-sectional width of the second annular protrusion is smaller than the cross-sectional width of the circular ring body but larger than the cross-sectional width of the first annular protrusion, and the cross-sectional width of the second annular protrusion is fan-shaped, and the cross-sectional height of the second annular protrusion gradually decreases from one end close to the inner wall surface of the circular ring body to one end of the outer wall surface of the circular ring body.
[0012] In the circular ring suitable for thick epitaxial growth of silicon carbide, preferably, the lower end surface of the first annular protrusion is a plane.
[0013] The ring suitable for silicon carbide thick epitaxial growth is preferably a silicon carbide ring.
[0014] The circular ring suitable for the thick epitaxial growth of silicon carbide is preferably a graphite ring.
[0015] A susceptor suitable for silicon carbide thick epitaxial growth, comprising any one of the above-mentioned rings, and further comprising:
[0016] A carrier plate and a silicon carbide substrate, wherein the carrier plate is provided with an annular boss, the diameter of the annular boss is smaller than the diameter of the carrier plate, the annular ring is sleeved on the outer edge of the annular boss, and the silicon carbide substrate is placed on the annular boss.
[0017] The base suitable for the thick epitaxial growth of silicon carbide, preferably, the thickness of the annular boss is the same as the thickness of the circular ring body.
[0018] In the base suitable for thick epitaxial growth of silicon carbide, preferably, the thickness of the silicon carbide substrate is smaller than the thickness of the second annular protrusion close to the inner wall surface of the annular body.
[0019] The base suitable for silicon carbide thick epitaxial growth is preferably configured such that the carrier plate is a graphite carrier plate.
[0020] The base suitable for silicon carbide thick epitaxial growth is preferably provided with a silicon carbide coating on the carrier plate.
[0021] The present invention adopts the above technical solution, which has the following advantages:
[0022] 1. The circular ring of the present invention is radially spliced with the silicon carbide substrate, and the thickness of the silicon carbide substrate at the splicing point is lower than the thickness of the circular ring. The circular ring is a beveled circular ring structure with a slope transition from the side where the silicon carbide substrate is located to the other side, which can reduce the disturbance of the airflow caused by excessive accumulation of by-products during growth and reduce the probability of by-product particles falling on the wafer surface.
[0023] 2. The present invention uses a beveled circular ring structure when growing thick epitaxy, which can reduce the disturbance of airflow caused by excessive accumulation of by-products during growth and reduce the probability of by-product particles falling on the wafer surface, thereby improving the silicon carbide epitaxial yield and creating higher value for the product. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 A schematic cross-sectional view of a conventional circular ring for thick epitaxial growth of silicon carbide provided by the present invention;
[0025] Figure 2 A schematic diagram of a circular ring suitable for silicon carbide thick epitaxial growth provided by an embodiment of the present invention;
[0026] Figure 3 for Figure 2 A cross-sectional view of
[0027] Figure 4 A schematic diagram of a ring suitable for silicon carbide thick epitaxial growth provided by another embodiment of the present invention;
[0028] Figure 5 for Figure 4 A cross-sectional view of
[0029] Figure 6 An exploded view of a susceptor suitable for thick epitaxial growth of silicon carbide provided in one embodiment of the present invention;
[0030] The reference numerals in the figures are as follows:
[0031] 1-annular body, 101-first annular protrusion, 102-second annular protrusion; 2-carrying plate, 201-annular boss; 3-silicon carbide substrate. DETAILED DESCRIPTION
[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.
[0033] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second", "third", "fourth" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
[0034] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outer side", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.
[0035] Silicon carbide has many other uses besides abrasives due to its stable chemical properties, high thermal conductivity, low thermal expansion coefficient and good wear resistance. For example, by applying silicon carbide powder to the inner wall of the turbine impeller or cylinder body with a special process, its wear resistance can be improved and its service life can be extended by 1 to 2 times. The high-grade refractory material made from it is resistant to thermal shock, small in size, light in weight, high in strength and has good energy-saving effect. Low-grade silicon carbide (containing about 85% SiC) is an excellent deoxidizer, which can speed up steelmaking, facilitate the control of chemical composition and improve the quality of steel. In addition, silicon carbide is also widely used in the production of silicon carbon rods for electric heating elements.
[0036] There are at least 70 crystalline forms of silicon carbide. α-Silicon carbide is the most common allomorph, formed at temperatures above 2000°C, and has a hexagonal crystal structure (similar to wurtzite). β-Silicon carbide, with a cubic structure, is similar to diamond and is formed at temperatures below 2000°C. Although it is attractive for use as a heterogeneous catalyst carrier because it has a higher unit surface area than the α-type, and another type of silicon carbide, μ-silicon carbide, is the most stable and has a more pleasant sound when it collides, these two forms have not been used commercially to date. Pure silicon carbide is a colorless and transparent crystal. Industrial silicon carbide is light yellow, green, blue or even black depending on the type and content of impurities it contains, and its transparency varies with its purity. The crystal structure of silicon carbide is divided into hexagonal or rhombohedral α-SiC and cubic β-SiC (called cubic silicon carbide). α-SiC has many different variants due to the different stacking sequences of carbon and silicon atoms in its crystal structure, and more than 70 types have been discovered. β-SiC transforms into α-SiC at above 2100°C. The industrial method of making silicon carbide is to refine it in a resistance furnace using high-quality quartz sand and petroleum coke. The refined silicon carbide blocks are crushed, acid-alkali washed, magnetically separated and screened or water-selected to produce products of various particle sizes.
[0037] Silicon carbide semiconductors have excellent properties such as large bandgap, excellent stability, high thermal conductivity, high critical breakdown field strength, and high saturated electron drift velocity. They are ideal semiconductor materials for making high-temperature, high-frequency, high-power, and strong radiation power electronic devices. Compared with traditional silicon devices, silicon carbide devices can work normally under an electric field strength 10 times that of silicon devices. The silicon carbide material used to make silicon carbide devices is usually a silicon carbide epitaxial wafer grown on a silicon carbide substrate. At present, silicon carbide epitaxial growth has been commercialized, and CVD (chemical vapor deposition) is usually used to grow silicon carbide epitaxial wafers.
[0038] At present, in the production of silicon carbide epitaxy, the rings used for growing thin epitaxy and the rings used for growing thick epitaxy are universal. However, due to the long growth time and high growth rate of thick epitaxy, the byproducts on the rings accumulate too quickly, especially the outermost ring of the ring will form an extremely high byproduct accumulation layer. The excessively high growth rate also makes these generated byproducts very loose, which will affect the transportation of gases during the long growth process and the byproduct particles will fall off on the silicon carbide wafer, affecting the subsequent yield.
[0039] Based on the above technical problems, the present invention provides a ring and a base suitable for the growth of thick silicon carbide epitaxy. When growing thick epitaxy, the ring uses a beveled ring structure to reduce the disturbance of the airflow caused by excessive accumulation of byproducts during growth and reduce the probability of byproduct particles falling on the wafer surface. This can improve the yield of silicon carbide epitaxy and create higher value for the product.
[0040] like Figure 1As described above, it is a schematic diagram of an existing ring for epitaxial growth of silicon carbide. The ring is a planar ring structure, which easily leads to the accumulation of byproducts on the ring too quickly, especially the outermost ring of the ring will form an extremely high byproduct accumulation layer. To solve this problem, the present application proposes the following solution.
[0041] like Figure 2 , 3 As shown, the present invention relates to a ring suitable for silicon carbide thick epitaxial growth, comprising:
[0042] A circular ring body 1, wherein the lower end face of the circular ring body 1 is provided with a first circular protrusion 101 extending downward, and the cross-sectional width of the first circular protrusion 101 is smaller than the cross-sectional width of the circular ring body 1; the upper end face of the circular ring body 1 is provided with a second circular protrusion 102 extending upward; the cross-sectional width of the second circular protrusion 102 is smaller than the cross-sectional width of the circular ring body 1 but larger than the cross-sectional width of the first circular protrusion 101, the cross-sectional shape of the second circular protrusion 102 is triangular, and the cross-sectional height of the second circular protrusion 102 gradually decreases from one end close to the inner wall of the circular ring body 1 to one end close to the outer wall of the circular ring body 1.
[0043] like Figure 4 , 5 As shown, the present invention also provides another ring suitable for silicon carbide thick epitaxial growth, comprising:
[0044] A circular ring body 1, wherein the lower end face of the circular ring body 1 is provided with a first circular protrusion 101 extending downward, and the cross-sectional width of the first circular protrusion 101 is smaller than the cross-sectional width of the circular ring body 1; the upper end face of the circular ring body 1 is provided with a second circular protrusion 102 extending upward; the cross-sectional width of the second circular protrusion 102 is smaller than the cross-sectional width of the circular ring body 1 but larger than the cross-sectional width of the first circular protrusion 101, and the cross-sectional shape of the second circular protrusion 102 is fan-shaped, and the cross-sectional height of the second circular protrusion 102 gradually decreases from one end close to the inner wall of the circular ring body 1 to one end close to the outer wall of the circular ring body 1.
[0045] Furthermore, if Figure 3 , 5 As shown, the lower end surface of the first annular protrusion 101 is a plane.
[0046] Furthermore, the ring provided by the present invention and suitable for silicon carbide thick epitaxial growth is a silicon carbide ring or a graphite ring.
[0047] like Figure 6 As shown, the present invention also provides a susceptor suitable for silicon carbide thick epitaxial growth, the aforementioned ring further comprising:
[0048] The carrier plate 2 and the silicon carbide substrate 3 are provided with an annular boss 201 on the carrier plate 2. The diameter of the annular boss 201 is smaller than the diameter of the carrier plate 2. The annular ring is sleeved on the outer edge of the annular boss 201. The silicon carbide substrate 3 is used to grow a silicon carbide film, and the carrier plate 2 is used to carry the silicon carbide substrate 3 into a high-temperature furnace to grow a silicon carbide film.
[0049] In a specific example of the present invention, the thickness of the annular boss 201 is the same as the thickness of the annular body 1. Preferably, the thickness of the silicon carbide substrate 3 is smaller than the thickness of the second annular protrusion 102 close to the inner wall of the annular body 1.
[0050] Furthermore, the carrier plate 2 is a graphite carrier plate, and a silicon carbide coating is provided on the carrier plate 2 .
[0051] The ring of the present invention is radially spliced with the silicon carbide substrate, the thickness of the silicon carbide substrate at the splicing point is lower than the thickness of the ring, and the ring is a beveled ring structure with a slope transition from the side where the silicon carbide substrate is located to the other side, which can reduce the disturbance of the airflow caused by the excessive accumulation of byproducts during growth and reduce the probability of byproduct particles falling on the wafer surface. This can improve the silicon carbide epitaxy yield and create higher value for the product.
[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A ring suitable for thick epitaxial growth of silicon carbide, characterized in that: include: A circular ring body (1), wherein the lower end surface of the circular ring body (1) is provided with a first circular protrusion (101) extending downward, and the cross-sectional width of the first circular protrusion (101) is smaller than the cross-sectional width of the circular ring body (1); The upper end surface of the annular body (1) is provided with a second annular protrusion (102) extending upward; the cross-sectional width of the second annular protrusion (102) is smaller than the cross-sectional width of the annular body (1) but larger than the cross-sectional width of the first annular protrusion (101); the cross-sectional shape of the second annular protrusion (102) is triangular, and the cross-sectional height of the second annular protrusion (102) gradually decreases from one end close to the inner wall surface of the annular body (1) to one end close to the outer wall surface of the annular body (1).
2. A ring suitable for thick epitaxial growth of silicon carbide, characterized in that: include: A circular ring body (1), wherein the lower end surface of the circular ring body (1) is provided with a first circular protrusion (101) extending downward, and the cross-sectional width of the first circular protrusion (101) is smaller than the cross-sectional width of the circular ring body (1); The upper end surface of the annular body (1) is provided with a second annular protrusion (102) extending upward; the cross-sectional width of the second annular protrusion (102) is smaller than the cross-sectional width of the annular body (1) but larger than the cross-sectional width of the first annular protrusion (101), and the cross-sectional width of the second annular protrusion (102) is fan-shaped, and the cross-sectional height of the second annular protrusion (102) gradually decreases from one end close to the inner wall surface of the annular body (1) to one end close to the outer wall surface of the annular body (1).
3. The ring suitable for silicon carbide thick epitaxial growth according to claim 1, characterized in that: The lower end surface of the first annular protrusion (101) is a plane.
4. The ring suitable for silicon carbide thick epitaxial growth according to claim 1, characterized in that: The ring is a silicon carbide ring.
5. The ring suitable for silicon carbide thick epitaxial growth according to claim 1, characterized in that: The ring is a graphite ring.
6. A base suitable for silicon carbide thick epitaxial growth, comprising the ring according to any one of claims 1 to 5, characterized in that: Also includes: A carrier plate (2) and a silicon carbide substrate (3), wherein an annular boss (201) is provided on the carrier plate (2), the diameter of the annular boss (201) is smaller than the diameter of the carrier plate (2), the circular ring is sleeved on the outer edge of the annular boss (201), and the silicon carbide substrate (3) is placed on the annular boss (201).
7. The susceptor suitable for silicon carbide thick epitaxial growth according to claim 6, characterized in that: The thickness of the annular boss (201) is the same as the thickness of the circular ring body (1).
8. The susceptor suitable for silicon carbide thick epitaxial growth according to claim 6, characterized in that: The thickness of the silicon carbide substrate (3) is smaller than the thickness of the second annular protrusion (102) close to the inner wall surface of the annular body (1).
9. The susceptor suitable for silicon carbide thick epitaxial growth according to claim 6, characterized in that: The carrier plate (2) is a graphite carrier plate.
10. The susceptor suitable for silicon carbide thick epitaxial growth according to claim 9, characterized in that: The carrier plate (2) is provided with a silicon carbide coating.