Silicon carbide epitaxial film and silicon carbide epitaxial equipment and method
By using 100% pure ammonia instead of nitrogen as an n-type doping source, ammonia gas is introduced during the growth of silicon carbide epitaxial film, which solves the problems of large changes in doping concentration and low yield caused by poor thermal chemical reaction of nitrogen, and improves the uniformity and process capability of silicon carbide epitaxial film.
Patent Information
- Application Number
- CN202411673786.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-21
- Publication Date
- 2025-03-07
AI Technical Summary
In the prior art, nitrogen gas has poor thermal chemical reaction. When it is used as an n-type doping source, the doping concentration of the silicon carbide epitaxial film changes greatly, resulting in a low yield rate.
100% pure ammonia gas is used to replace nitrogen as an n-type doping source, and ammonia gas is introduced during the growth of the silicon carbide epitaxial film, and high-temperature chemical synthesis is carried out through the silicon carbide epitaxial equipment to form a uniform silicon carbide epitaxial film.
The uniformity of the silicon carbide epitaxial film has been greatly improved, the Cpk technical indicators of process capabilities have been improved, the production yield has been effectively improved, and the overall economic benefits have been increased.
Smart Images
Figure CN119584615A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a silicon carbide epitaxial film and a silicon carbide epitaxial device and method. Background Art
[0002] Silicon carbide epitaxial film refers to a specific single crystal film grown on a silicon carbide substrate through an epitaxial process, which is consistent with the substrate lattice, has high purity and low defects. Silicon carbide devices made of it are widely used in industries such as automobiles. Cpk refers to the process capability index of silicon carbide epitaxial film. When the Cpk of silicon carbide epitaxial film is greater than 1.67, it can be used in automobiles.
[0003] In the process of growing silicon carbide epitaxial film, an n-type doping source needs to be introduced to form an n-type doped silicon carbide epitaxial film. The uniformity and consistency of the doping directly affect the uniformity and Cpk index of the silicon carbide epitaxial film. Nitrogen is widely used as an n-type doping source in the growth process of silicon carbide epitaxial film because of its low cost and high safety.
[0004] However, in the above-mentioned prior art, nitrogen has a poor thermochemical reaction. When it is used as an n-type doping source, the doping concentration of the silicon carbide epitaxial film varies greatly, resulting in a low yield. Summary of the invention
[0005] The purpose of the present invention is to provide a silicon carbide epitaxial film and a silicon carbide epitaxial device and method, aiming to solve the technical problem in the prior art that nitrogen has a poor thermochemical reaction and when it is used as an n-type doping source, the doping concentration of the silicon carbide epitaxial film varies greatly, resulting in a low yield rate.
[0006] To achieve the above object, the present invention adopts a silicon carbide epitaxial film, which includes a silicon carbide substrate, an N-type buffer layer and an N-type drift layer, wherein the N-type buffer layer is arranged between the silicon carbide substrate and the N-type drift layer.
[0007] The present invention also provides a silicon carbide epitaxial device for preparing the silicon carbide epitaxial film as described above.
[0008] It includes a stainless steel cavity, a support seat, a graphite carrier, a cylinder, a plurality of gas guide plates, a first heating component and a second heating component. The cylinder is fixedly connected to the stainless steel cavity and is located inside the stainless steel cavity. The support seat passes through the stainless steel cavity and is rotatably connected to the stainless steel cavity. The graphite carrier is arranged at the upper end of the support seat. The plurality of gas guide plates are all arranged inside the stainless steel cavity. The first heating component is arranged inside the stainless steel cavity, and the second heating component is arranged inside the support seat.
[0009] Wherein, the first heating component includes a first heater and a first thermal insulation device, the first heater is arranged on the outside of the cylinder, and the first thermal insulation device is arranged on the outside of the first heater.
[0010] The second heating assembly includes a second heater and a second thermal insulation device, the second thermal insulation device is arranged inside the support seat, and the second heater is arranged above the second thermal insulation device.
[0011] Wherein, the silicon carbide epitaxial device further includes a temperature detector, and the temperature detector is arranged at the upper end of the stainless steel cavity.
[0012] Wherein, an exhaust hole is arranged at the bottom of the stainless steel cavity.
[0013] The present invention also provides a silicon carbide epitaxial growth method, which is applied to the silicon carbide epitaxial growth device described above, and comprises the following steps:
[0014] Step 1: firstly placing the silicon carbide substrate on the graphite carrier;
[0015] Step 2: Then, hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity;
[0016] Step 3: Then, heating the silicon carbide substrate to 1650° C. by using the first heater and the second heater;
[0017] Step 4: Then, silane and propane are introduced into the interior of the stainless steel cavity respectively, and after high temperature, the silane and propane are chemically synthesized into a silicon carbide epitaxial film;
[0018] Step 5: Finally, 100% pure ammonia gas is introduced during the film growth process to form an n-type doped silicon carbide epitaxial film.
[0019] A silicon carbide epitaxial film and silicon carbide epitaxial device and method of the present invention, when used specifically, firstly place the silicon carbide substrate on the graphite carrier, then use hydrogen as a carrier gas to pass into the interior of the stainless steel cavity, then heat the silicon carbide substrate to 1650° C. by the first heater and the second heater, then pass silane and propane into the interior of the stainless steel cavity respectively, after high temperature, the silane and propane are chemically synthesized into a silicon carbide epitaxial film, and finally, 100% pure ammonia is passed in the film growth process to form an n-type doped silicon carbide epitaxial film. By using ammonia instead of nitrogen as the n-type doping source, the uniformity of the silicon carbide epitaxial film and the process capability Cpk technical index can be greatly improved, so as to effectively improve the production yield and increase the comprehensive economic benefits. This method can effectively solve the problem in the prior art that the thermochemical reaction of nitrogen is poor, and when it is used as an n-type doping source, the doping concentration of the silicon carbide epitaxial film varies greatly, resulting in a low yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 It is a schematic diagram of the structure of the silicon carbide epitaxial film of the present invention.
[0022] Figure 2 It is a schematic structural diagram of the silicon carbide epitaxial device of the present invention.
[0023] Figure 3 This is a growth diagram of a silicon carbide epitaxial film made using nitrogen as an n-type doping source.
[0024] Figure 4 This is a growth diagram of a silicon carbide epitaxial film made using ammonia as an n-type doping source according to the present invention.
[0025] 101-silicon carbide substrate, 102-N-type buffer layer, 103-N-type drift layer, 104-stainless steel cavity, 105-exhaust hole, 106-support seat, 107-graphite carrier, 108-cylinder, 109-gas guide plate, 110-first heater, 111-first thermal insulation and heat preservation device, 112-second heater, 113-second thermal insulation and heat preservation device, 114-temperature measuring device. DETAILED DESCRIPTION
[0026] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.
[0027] See also Figure 1 , Figure 1 is a schematic structural diagram of a silicon carbide epitaxial film of the present invention,
[0028] The present invention provides a silicon carbide epitaxial film, comprising a silicon carbide substrate 101 , an N-type buffer layer 102 and an N-type drift layer 103 , wherein the N-type buffer layer 102 is disposed between the silicon carbide substrate 101 and the N-type drift layer 103 .
[0029] In this embodiment, the silicon carbide substrate 101 is first placed on the graphite carrier 107, and then hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity 104. After that, the silicon carbide substrate 101 is heated to 1650° C. by the first heater 110 and the second heater 112, and then silane and propane are respectively introduced into the interior of the stainless steel cavity 104. After high temperature, silane and propane are chemically synthesized into a silicon carbide epitaxial film. Finally, 100% pure ammonia is introduced during the film growth process to form an n-type doped silicon carbide epitaxial film. By using ammonia instead of nitrogen as the n-type doping source, the uniformity of the silicon carbide epitaxial film and the process capability Cpk technical index can be greatly improved, thereby effectively improving the production yield and increasing the overall economic benefits.
[0030] See also Figure 2 , Figure 2 is a schematic diagram of the structure of the silicon carbide epitaxial device of the present invention. The present invention also provides a silicon carbide epitaxial device for preparing the silicon carbide epitaxial film as described above.
[0031] It includes a stainless steel cavity 104, a support seat 106, a graphite carrier 107, a cylinder 108, a plurality of gas guide plates 109, a first heating component and a second heating component. The cylinder 108 is fixedly connected to the stainless steel cavity 104 and is located inside the stainless steel cavity 104. The support seat 106 passes through the stainless steel cavity 104 and is rotatably connected to the stainless steel cavity 104. The graphite carrier 107 is arranged at the upper end of the support seat 106. The plurality of gas guide plates 109 are all arranged inside the stainless steel cavity 104. The first heating component is arranged inside the stainless steel cavity 104, and the second heating component is arranged inside the support seat 106.
[0032] In this embodiment, the silicon carbide substrate 101 is first placed on the graphite carrier 107, and then hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity 104. The silicon carbide substrate 101 is then heated to 1650° C. by the first heating component and the second heating component. Then, silane and propane are respectively introduced into the interior of the stainless steel cavity 104. After high temperature, silane and propane are chemically synthesized into a silicon carbide epitaxial film. Finally, 100% pure ammonia is introduced during the film growth process to form an n-type doped silicon carbide epitaxial film.
[0033] Furthermore, the first heating assembly includes a first heater 110 and a first thermal insulation device 111 . The first heater 110 is disposed on the outside of the cylinder 108 , and the first thermal insulation device 111 is disposed on the outside of the first heater 110 .
[0034] In this embodiment, the interior of the stainless steel cavity 104 is heated by the first heater 110 , and the stainless steel cavity 104 is kept warm by the first heat insulation device 111 .
[0035] Furthermore, the second heating assembly includes a second heater 112 and a second thermal insulation device 113 , the second thermal insulation device 113 is disposed inside the support seat 106 , and the second heater 112 is disposed above the second thermal insulation device 113 .
[0036] In this embodiment, the graphite carrier 107 is heated by the second heater 112 and is kept warm by the second heat insulation device 113 .
[0037] Furthermore, the silicon carbide epitaxial device also includes a temperature detector 114 , and the temperature detector 114 is disposed at the upper end of the stainless steel cavity 104 .
[0038] In this embodiment, the temperature inside the stainless steel cavity 104 is measured by the temperature detector 114 .
[0039] Furthermore, an exhaust hole 105 is provided at the bottom of the stainless steel cavity 104 .
[0040] In this embodiment, the air in the stainless steel cavity 104 is exhausted through the exhaust hole 105 .
[0041] See also Figure 3 and Figure 4 , Figure 3 This is a growth diagram of an existing silicon carbide epitaxial film made using nitrogen as an n-type doping source. Figure 4The present invention is a growth diagram of a silicon carbide epitaxial film made by using ammonia as an n-type doping source. The present invention also provides a silicon carbide epitaxial method, which is applied to the silicon carbide epitaxial device described above, and comprises the following steps:
[0042] Step 1: firstly, placing the silicon carbide substrate 101 on the graphite carrier 107;
[0043] Step 2: Then, hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity 104;
[0044] Step 3: Then, the silicon carbide substrate 101 is heated to 1650° C. by the first heater 110 and the second heater 112 ;
[0045] Step 4: Then, silane and propane are introduced into the interior of the stainless steel cavity 104 respectively, and after high temperature, the silane and propane are chemically synthesized into a silicon carbide epitaxial film;
[0046] Step 5: Finally, 100% pure ammonia gas is introduced during the film growth process to form an n-type doped silicon carbide epitaxial film.
[0047] The present invention provides a silicon carbide epitaxial film and a silicon carbide epitaxial device and method. When used, the silicon carbide substrate 101 is first placed on the graphite carrier 107, and then hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity 104. Then, the silicon carbide substrate 101 is heated to 1650° C. by the first heater 110 and the second heater 112, and then silane and propane are respectively passed into the interior of the stainless steel cavity 104. After high temperature, silane and propane are chemically synthesized into carbon. A silicon carbide epitaxial film is grown, and finally 100% pure ammonia is introduced during the film growth process to become an n-type doped silicon carbide epitaxial film. By using ammonia instead of nitrogen as the n-type doping source, the uniformity of the silicon carbide epitaxial film and the process capability Cpk technical index can be greatly improved, thereby effectively improving the production yield and increasing the overall economic benefits. This method can effectively solve the problem in the prior art that nitrogen has a poor thermochemical reaction. When it is used as an n-type doping source, the doping concentration of the silicon carbide epitaxial film varies greatly, resulting in a low yield.
[0048] The following table is a comparison table of concentration uniformity (Std.) and concentration Cpk of silicon carbide epitaxial films made by the n-type doping source used in the prior art and the n-type doping source used in the present invention.
[0049]
[0050] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.
Claims
1. A silicon carbide epitaxial film, characterized in that: The invention comprises a silicon carbide substrate, an N-type buffer layer and an N-type drift layer, wherein the N-type buffer layer is arranged between the silicon carbide substrate and the N-type drift layer.
2. A silicon carbide epitaxial device for preparing the silicon carbide epitaxial film according to claim 1, characterized in that: It includes a stainless steel cavity, a support seat, a graphite carrier, a cylinder, a plurality of gas guide plates, a first heating component and a second heating component. The cylinder is fixedly connected to the stainless steel cavity and is located inside the stainless steel cavity. The support seat passes through the stainless steel cavity and is rotatably connected to the stainless steel cavity. The graphite carrier is arranged at the upper end of the support seat. The plurality of gas guide plates are all arranged inside the stainless steel cavity. The first heating component is arranged inside the stainless steel cavity, and the second heating component is arranged inside the support seat.
3. The silicon carbide epitaxial device according to claim 2, characterized in that: The first heating assembly includes a first heater and a first heat insulation device. The first heater is arranged on the outside of the cylinder, and the first heat insulation device is arranged on the outside of the first heater.
4. The silicon carbide epitaxial device according to claim 3, characterized in that: The second heating assembly includes a second heater and a second thermal insulation device, wherein the second thermal insulation device is disposed inside the support seat, and the second heater is disposed above the second thermal insulation device.
5. The silicon carbide epitaxial device according to claim 4, characterized in that: The silicon carbide epitaxial device further comprises a temperature detector, which is arranged at the upper end of the stainless steel cavity.
6. The silicon carbide epitaxial device according to claim 5, characterized in that: An exhaust hole is arranged at the bottom of the stainless steel cavity.
7. A silicon carbide epitaxial growth method, applied to the silicon carbide epitaxial growth device as claimed in claim 6, characterized in that: The steps include: Step 1: firstly placing the silicon carbide substrate on the graphite carrier; Step 2: Then, hydrogen is used as a carrier gas to pass into the interior of the stainless steel cavity; Step 3: Then, heating the silicon carbide substrate to 1650° C. by using the first heater and the second heater; Step 4: Then, silane and propane are introduced into the interior of the stainless steel cavity respectively, and after high temperature, the silane and propane are chemically synthesized into a silicon carbide epitaxial film; Step 5: Finally, 100% pure ammonia gas is introduced during the film growth process to form an n-type doped silicon carbide epitaxial film.