Preparation method of heteroepitaxial diamond silicon carbide composite wafer

Abstract

The invention belongs to the technical field of diamond heat dissipation materials, and particularly discloses a preparation method of a heteroepitaxy diamond silicon carbide composite wafer, which comprises the following steps of: loading a synthetic block into a cubic press, processing by adopting a segmented boosting process, melting a nickel-manganese-cobalt alloy sheet in each layer, and enabling a silicon carbide wafer to be in contact with one surface of the alloy sheet, silicon in the silicon carbide wafer can be fused into the nickel-manganese-cobalt alloy sheet, and the residual carbon atoms in the silicon carbide wafer can be rearranged in a diamond crystal structure due to the fact that the high-temperature and ultrahigh-pressure environment in the synthesis cavity is located in a stable region of the diamond, so that the heteroepitaxial diamond silicon carbide composite wafer is obtained. According to the method, boron is doped on the diamond surface, phosphorus is doped on the silicon carbide surface, a PN node structure which is the most basic for chip manufacturing can be integrated on a wafer, a semiconductor chip which is higher in voltage resistance degree, higher in operation speed, higher in high-temperature resistance and smaller in manufacturing procedure is manufactured, and the method has important strategic significance for microelectronic industry and high-performance chip development; and 10-40 heteroepitaxial diamond silicon carbide composite wafers can be synthesized at a time.

Description

Technical Field

[0001] The invention relates to the field of semiconductor material preparation, in particular to a method for preparing a heteroepitaxial diamond silicon carbide composite wafer. Background Art

[0002] Silicon carbide (SiC) has a special crystal structure that uses a hexagonal close-packed structure similar to diamond. This structure gives silicon carbide excellent thermal conductivity and high temperature resistance. Compared with traditional silicon materials, silicon carbide has a larger band gap width, which can provide a higher electron band spacing, thereby achieving higher electron mobility and lower leakage current. In addition, silicon carbide also has a higher electron saturation drift velocity and a lower material resistivity, providing better performance for high-power applications. These characteristics make silicon carbide wafers have broad application prospects in many fields. Silicon carbide wafers can be used to manufacture high-power density switching devices such as power modules for electric vehicles and solar inverters. Its high thermal conductivity and high temperature resistance enable it to provide stable operating performance in high temperature environments, achieving more efficient energy conversion and more compact design.

[0003] Diamond also has the characteristics of wide bandgap, high breakdown field strength, high carrier saturation drift velocity, etc. These characteristics make diamond have extensive and irreplaceable application advantages and prospects under high frequency and high voltage conditions. The bandgap width of diamond is 5.5eV, the carrier mobility is 3 times that of silicon material, and it has extremely low intrinsic carrier concentration at room temperature and has excellent high temperature resistance. These characteristics make diamond a more suitable semiconductor material than silicon carbide.

[0004] If silicon carbide and diamond can be combined as a semiconductor material, it will undoubtedly be a better way. However, the main bottleneck restricting the development of diamond semiconductor performance is that in addition to the difficulty in mass-producing single-crystal diamond wafers at low cost, the high concentration of N-type doping of diamond will still be a bottleneck that is difficult to break through in the short term. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a heteroepitaxial diamond silicon carbide composite wafer.

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions: The object of the present invention is to provide a method for preparing a heteroepitaxial diamond silicon carbide composite wafer, comprising the following steps: S1. Assemble the diamond silicon carbide composite wafer synthesis block: the synthesis block includes a pyrophyllite square tube with a cylindrical cavity inside, the inner wall of the cylindrical cavity of the pyrophyllite square tube is embedded with a composite pyrophyllite tube, the inner diameter of the composite pyrophyllite tube is the same as the inner diameter of the pyrophyllite square tube; a heating tube is sleeved in the composite pyrophyllite tube, heating plates are provided at both ends of the heating tube, an insulating cup is sleeved in the heating tube, and sealing insulating plates are provided at both ends of the insulating cup; composite pyrophyllite sealing blocks and pyrophyllite sealing blocks are provided at the two ends of the composite pyrophyllite tube from the inside to the outside, a conductive steel ring is provided through the center of the composite pyrophyllite sealing block and the pyrophyllite sealing block, and the conductive steel ring The inner end face of the insulating cup contacts the outer end face of the heating plate; a diamond silicon carbide composite wafer synthesis block is sleeved in the insulating cup, and the diamond silicon carbide composite wafer synthesis block includes a carbon tube sleeved on the inner wall of the insulating cup, and a plugging carbon sheet is respectively provided in the top and the end of the carbon tube, and a plurality of isolation carbon sheets are provided in the carbon tube from top to bottom, and a nickel-manganese-cobalt alloy sheet and a silicon carbide wafer sheet are sequentially laid between two adjacent isolation carbon sheets from bottom to top; the lower end face of the isolation carbon sheet of the lowest layer in the carbon tube contacts the upper end face of the plugging carbon sheet at the lower end of the carbon tube, and the upper end face of the isolation carbon sheet of the highest layer in the carbon tube contacts the lower end face of the plugging carbon sheet at the upper end of the carbon tube; S2. Preparation of diamond silicon carbide composite wafers: Load the above-mentioned synthesis block into the synthesis chamber of a six-sided top press, and use a segmented pressure-increasing process to increase the pressure in the synthesis chamber to 4.5~6GPa, and the temperature reaches 1400~1700 degrees and is maintained for 20~80 minutes. Each layer of the nickel-manganese-cobalt alloy sheet is melted, and the silicon carbide wafer contacts one side of the nickel-manganese-cobalt alloy sheet. The silicon in the silicon carbide wafer will be integrated into the nickel-manganese-cobalt alloy sheet. Because the high temperature and ultra-high pressure environment in the synthesis chamber is in the stable zone of diamond, the remaining carbon atoms in the silicon carbide wafer are rearranged in a diamond crystal structure, and finally heteroepitaxially grow into a diamond layer silicon carbide composite wafer, and the diamond layer silicon carbide composite wafer is taken out of the carbon tube and cooled to room temperature.

[0007] Furthermore, in the nickel-manganese-cobalt alloy sheet, the weight percentage of nickel is 50% to 80%; the weight percentage of manganese is 15% to 30%; and the weight percentage of cobalt is 1% to 10%.

[0008] Furthermore, the thickness of the silicon carbide wafer is 0.2~2mm.

[0009] Furthermore, the thickness of the nickel-manganese-cobalt alloy sheet is 0.1-2 mm.

[0010] Compared with the prior art, the present invention can integrate the most basic PN junction structure for chip manufacturing on the wafer by doping boron on the diamond surface and phosphorus on the silicon carbide surface, thereby manufacturing semiconductor chips with higher voltage resistance, faster running speed, higher temperature resistance and smaller process. It has important strategic significance for the microelectronics industry and high-performance chip development; and 10 to 40 diamond silicon carbide composite wafers can be synthesized at a single time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of the diamond silicon carbide composite wafer synthesis block assembled in the present invention. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0013] A method for preparing a heteroepitaxial diamond silicon carbide composite wafer comprises the following steps: S1. Assembling diamond silicon carbide composite wafer synthesis block: Figure 1 As shown, the synthesis block includes a pyrophyllite square tube 1 with a cylindrical cavity inside, a composite pyrophyllite tube 2 is embedded in the inner wall of the cylindrical cavity of the pyrophyllite square tube 1, and the inner diameter of the composite pyrophyllite tube 2 is the same as the inner diameter of the pyrophyllite square tube; a heating tube 3 is sleeved in the composite pyrophyllite tube 2, and heating plates 4 are provided at both ends of the heating tube 3, and an insulating cup 5 (dolomite cup) is sleeved in the heating tube 3, and blocking insulating plates 6 are provided at both ends of the insulating cup 5; composite pyrophyllite blocking blocks and pyrophyllite blocking blocks 11 are provided at the two ends of the composite pyrophyllite tube 2 from the inside to the outside, and a conductive steel ring 12 is provided through the center of the composite pyrophyllite blocking blocks and the pyrophyllite blocking blocks 11, and the inner end face of the conductive steel ring 12 is in contact with the outer end face of the heating plates 4; a diamond silicon carbide composite wafer synthesis block is sleeved in the insulating cup 5, and the diamond silicon carbide composite wafer synthesis block is The block includes a carbon tube 7 sleeved on the inner wall of an insulating cup 5, a plugging carbon sheet 8 is respectively arranged at the top and the end of the carbon tube 7, a plurality of isolation carbon sheets 9 are arranged from top to bottom in the carbon tube 7, a nickel-manganese-cobalt alloy sheet 10 and a silicon carbide wafer sheet 13 are sequentially laid from bottom to top between two adjacent isolation carbon sheets 9, wherein the weight percentage of nickel in the nickel-manganese-cobalt alloy sheet 10 is 50%-80%; the weight percentage of manganese is 15%-30%; the weight percentage of cobalt is 1%-10%; the thickness of the nickel-manganese-cobalt alloy sheet 10 is 0.1-2mm, and the thickness of the silicon carbide wafer sheet 13 is 0.2-2mm; the lower end face of the isolation carbon sheet at the bottom layer in the carbon tube 7 contacts the upper end face of the plugging carbon sheet 8 at the lower end of the carbon tube 7, and the upper end face of the isolation carbon sheet at the top layer in the carbon tube contacts the lower end face of the plugging carbon sheet 8 at the upper end of the carbon tube 7; S2. Preparation of diamond silicon carbide composite wafer: The above-mentioned synthesis block is loaded into the synthesis chamber of the six-sided top press, and the pressure in the synthesis chamber is increased to 4.5~6GPa by a staged pressure-increasing process, and the temperature reaches 1400~1700 degrees and is maintained for 20~80 minutes. Each layer of the nickel-manganese-cobalt alloy sheet 10 melts, and the silicon carbide wafer 13 contacts one side of the nickel-manganese-cobalt alloy sheet 10. The silicon in the silicon carbide wafer 13 will be integrated into the nickel-manganese-cobalt alloy sheet 10. Because the high temperature and ultra-high pressure environment in the synthesis chamber is in the stable zone of diamond, the remaining carbon atoms in the silicon carbide wafer 13 are rearranged in a diamond crystal structure, and finally a heteroepitaxial diamond layer silicon carbide composite wafer with a thickness of 0.2~2mm is generated, that is, one side is diamond and the other side is silicon carbide; the diamond layer silicon carbide composite wafer is taken out from the carbon tube 7 and cooled to room temperature.

[0014] In the actual preparation process, different synthesis pressures and times can be adjusted in the chamber to form lattice defects of different concentrations in the diamond layer in the composite wafer, reserving vacancies for subsequent diamond layer doping. The final product is made into a semiconductor power device by doping the diamond layer with boron and the silicon carbide layer with phosphorus.

[0015] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a heteroepitaxial diamond silicon carbide composite wafer, characterized in that: The following steps are involved: S1. Assemble the diamond silicon carbide composite wafer synthesis block: the synthesis block includes a pyrophyllite square tube with a cylindrical cavity inside, the inner wall of the cylindrical cavity of the pyrophyllite square tube is embedded with a composite pyrophyllite tube, the inner diameter of the composite pyrophyllite tube is the same as the inner diameter of the pyrophyllite square tube; a heating tube is sleeved in the composite pyrophyllite tube, heating plates are provided at both ends of the heating tube, an insulating cup is sleeved in the heating tube, and sealing insulating plates are provided at both ends of the insulating cup; composite pyrophyllite sealing blocks and pyrophyllite sealing blocks are provided at the two ends of the composite pyrophyllite tube from the inside to the outside, a conductive steel ring is provided through the center of the composite pyrophyllite sealing block and the pyrophyllite sealing block, and the conductive steel ring The inner end face of the insulating cup contacts the outer end face of the heating plate; a diamond silicon carbide composite wafer synthesis block is sleeved in the insulating cup, and the diamond silicon carbide composite wafer synthesis block includes a carbon tube sleeved on the inner wall of the insulating cup, and a plugging carbon sheet is respectively provided in the top and the end of the carbon tube, and a plurality of isolation carbon sheets are provided in the carbon tube from top to bottom, and a nickel-manganese-cobalt alloy sheet and a silicon carbide wafer sheet are sequentially laid between two adjacent isolation carbon sheets from bottom to top; the lower end face of the isolation carbon sheet of the lowest layer in the carbon tube contacts the upper end face of the plugging carbon sheet at the lower end of the carbon tube, and the upper end face of the isolation carbon sheet of the highest layer in the carbon tube contacts the lower end face of the plugging carbon sheet at the upper end of the carbon tube; S2. Preparation of diamond silicon carbide composite wafers: Load the above-mentioned synthesis block into the synthesis chamber of a six-sided top press, and use a segmented pressure-increasing process to increase the pressure in the synthesis chamber to 4.5~6GPa, and the temperature reaches 1400~1700 degrees and is maintained for 20~80 minutes. Each layer of the nickel-manganese-cobalt alloy sheet is melted, and the silicon carbide wafer contacts one side of the nickel-manganese-cobalt alloy sheet. The silicon in the silicon carbide wafer will be integrated into the nickel-manganese-cobalt alloy sheet. Because the high temperature and ultra-high pressure environment in the synthesis chamber is in the stable zone of diamond, the remaining carbon atoms in the silicon carbide wafer are rearranged in a diamond crystal structure, and finally a heteroepitaxial diamond layer silicon carbide composite wafer is generated. The diamond layer silicon carbide composite wafer is taken out of the carbon tube and cooled to room temperature.

2. The method for preparing a heteroepitaxial diamond silicon carbide composite wafer according to claim 1, characterized in that: In the nickel-manganese-cobalt alloy sheet, the weight percentage of nickel is 50% to 80%; the weight percentage of manganese is 15% to 30%; and the weight percentage of cobalt is 1% to 10%.

3. The method for preparing a heteroepitaxial diamond silicon carbide composite wafer according to claim 1, characterized in that: The thickness of the silicon carbide wafer is 0.2-2 mm.

4. The method for preparing a heteroepitaxial diamond silicon carbide composite wafer according to claim 1, characterized in that: The thickness of the nickel-manganese-cobalt alloy sheet is 0.1-2.

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