Method for preparing diamond wafer from silicon carbide wafer

Abstract

The invention belongs to the technical field of diamond heat dissipation materials, and particularly discloses a method for preparing a diamond wafer from a silicon carbide wafer, which comprises the following steps of: loading a synthetic block into a cubic press, processing by adopting a segmented boosting process, and melting nickel-manganese-cobalt alloy sheets on two sides of the silicon carbide wafer between every two layers of isolation carbon sheets to obtain a diamond wafer; silicon in the silicon carbide wafer can be fused into the nickel-manganese-cobalt alloy sheet, and finally the diamond wafer is generated. The high-temperature ultrahigh-pressure heteroepitaxy mode is adopted, the silicon carbide wafer is used as the raw material, batch manufacturing of the high-performance low-cost diamond wafer is achieved on a large domestic cubic press, and compared with an existing single crystal diamond process, the growth speed is high, the market prospect is wide, and the production cost is low. The problem of low-cost manufacturing of basic raw materials for semiconductor development is solved; and 10-40 diamond wafers of 1-4 inches 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 diamond wafer by using a silicon carbide wafer. Background Art

[0002] Diamond is known for its high thermal conductivity. The thermal conductivity of single crystal diamond can reach 2200-2600 W / (m・K), which is 4-5 times that of copper and silver, 4 times greater than silicon carbide (SiC), 13 times greater than silicon (Si), and 43 times greater than gallium arsenide (GaAs). This high thermal conductivity makes diamond an ideal heat dissipation material, which can quickly conduct away the heat generated by semiconductor chips during operation, effectively avoiding problems such as performance degradation and reduced reliability of chips due to excessive temperature.

[0003] Diamond also has characteristics such as wide bandgap, high breakdown field strength, and high carrier saturation drift velocity. 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 strong competitor for the next generation of semiconductor materials.

[0004] In summary, the reasons why diamond wafers are used as semiconductor materials mainly include their high thermal conductivity, thermal expansion coefficient matching that of semiconductor materials, wide bandgap, high carrier mobility, and excellent high temperature resistance. These characteristics together give diamond a wide range of application prospects in the semiconductor field. ‌ However, the main bottleneck restricting the development of diamond semiconductor performance is that single-crystal diamond wafers are difficult to manufacture in large quantities and at low cost. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a diamond wafer from a silicon carbide 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 diamond wafer from a silicon carbide wafer, comprising the following steps: S1. Assemble high-temperature ultrahigh-pressure heteroepitaxial diamond wafer synthesis block: the synthesis block includes a pyrophyllite square tube with a cylindrical cavity inside, a composite pyrophyllite tube is embedded in the inner wall of the cylindrical cavity of the pyrophyllite square tube, and 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 arranged at both ends of the heating tube, an insulating cup is sleeved in the heating tube, and sealing insulating plates are arranged at both ends of the insulating cup; composite pyrophyllite sealing blocks and pyrophyllite sealing blocks are arranged at the two ends of the composite pyrophyllite tube from the inside to the outside, and a conductive steel ring is arranged through the center of the composite pyrophyllite sealing block and the pyrophyllite sealing block, and the inner end face of the conductive steel ring is aligned with the heating plate. The outer end faces of the heat plate are in contact; a high-temperature ultra-high-pressure heteroepitaxial diamond wafer synthesis block is sleeved in the insulating cup, and the high-temperature ultra-high-pressure heteroepitaxial diamond 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 1, a silicon carbide wafer sheet and a nickel-manganese-cobalt alloy sheet 2 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 high-temperature and ultra-high-pressure heteroepitaxial diamond 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 100~180 minutes. The nickel-manganese-cobalt alloy sheets on both sides of the silicon carbide wafer between each two layers of isolation carbon sheets are melted, and the silicon inside the silicon carbide wafer will be integrated into the nickel-manganese-cobalt alloy sheets. 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 will be rearranged in a diamond crystal structure, and finally a diamond wafer is generated. The diamond wafer is taken out of the carbon tube and cooled to room temperature.

[0007] Furthermore, in the nickel-manganese-cobalt alloy sheet 1 and the nickel-manganese-cobalt alloy sheet 2, 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 1 and the nickel-manganese-cobalt alloy sheet 2 are both 0.1-2 mm.

[0010] Compared with the prior art, the present invention adopts high-temperature ultra-high-pressure heteroepitaxial growth method, takes silicon carbide wafers as raw materials, and realizes batch production of high-performance and low-cost diamond wafers on a large domestic six-sided top press. Compared with the existing single crystal diamond process, the present invention has a fast growth rate and broad market prospects, and solves the problem of low-cost manufacturing of basic raw materials for the development of the fourth-generation semiconductor; and it can achieve 1~4 inches, and 10~40 diamond wafers can be synthesized at a single time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of the high-temperature and ultra-high-pressure heteroepitaxial diamond wafer synthesis block assembled by 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 diamond wafer from a silicon carbide wafer comprises the following steps: S1. Assemble high temperature and ultra-high pressure heteroepitaxial diamond wafer synthesis block: Figure 1As shown, the synthesis block includes a pyrophyllite square tube 1 with a cylindrical cavity inside, and 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 sequentially arranged at the two ends of the composite pyrophyllite tube 2 from the inside to the outside, and a conductive steel ring 12 is arranged 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 high-temperature ultra-high-pressure heteroepitaxial diamond wafer synthesis block is sleeved in the insulating cup 5, and the high-temperature ultra-high-pressure heteroepitaxial diamond wafer synthesis block includes a heating plate 4 sleeved on the inner wall of the insulating cup 5. A carbon tube 7, wherein 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 in the carbon tube 7 from top to bottom, and a nickel-manganese-cobalt alloy sheet 10, a silicon carbide wafer sheet 14 and a nickel-manganese-cobalt alloy sheet 2 13 are sequentially laid between two adjacent isolation carbon sheets 9 from bottom to top, wherein the weight percentage of nickel in the nickel-manganese-cobalt alloy sheet 10 and the nickel-manganese-cobalt alloy sheet 2 13 is 50% to 80%; the weight percentage of manganese is 15% to 30%; the weight percentage of cobalt is 1% to 10%; the thickness of the nickel-manganese-cobalt alloy sheet 10 and the nickel-manganese-cobalt alloy sheet 2 13 is 0.1-2mm, and the thickness of the silicon carbide wafer sheet 13 is 0.2 to 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 high-temperature and ultra-high-pressure heteroepitaxial diamond wafers: 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 segmented pressure-increasing process. The temperature reaches 1400~1700 degrees and is maintained for 20~180 minutes. The nickel-manganese-cobalt alloy sheets on both sides of the silicon carbide wafer 14 between each two layers of isolation carbon sheets 9 are melted, and the silicon inside the silicon carbide wafer 14 will be integrated into the nickel-manganese-cobalt alloy sheets. 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 14 will be rearranged in a diamond crystal structure, and finally a diamond wafer with a thickness of 0.2~2mm is generated. The diamond wafer is taken out of the carbon tube and cooled to room temperature.

[0014] The diamond wafer in this embodiment is grown and can therefore be mass-produced.

[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 diamond wafer from a silicon carbide wafer, It is characterized in that The following steps are involved: S1. Assemble high-temperature ultrahigh-pressure heteroepitaxial diamond wafer synthesis block: the synthesis block includes a pyrophyllite square tube with a cylindrical cavity inside, a composite pyrophyllite tube is embedded in the inner wall of the cylindrical cavity of the pyrophyllite square tube, and 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 arranged at both ends of the heating tube, an insulating cup is sleeved in the heating tube, and sealing insulating plates are arranged at both ends of the insulating cup; composite pyrophyllite sealing blocks and pyrophyllite sealing blocks are arranged at the two ends of the composite pyrophyllite tube from the inside to the outside, and a conductive steel ring is arranged through the center of the composite pyrophyllite sealing block and the pyrophyllite sealing block, and the inner end face of the conductive steel ring is aligned with the heating plate. The outer end faces of the heat plate are in contact; a high-temperature ultra-high-pressure heteroepitaxial diamond wafer synthesis block is sleeved in the insulating cup, and the high-temperature ultra-high-pressure heteroepitaxial diamond 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 1, a silicon carbide wafer sheet and a nickel-manganese-cobalt alloy sheet 2 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 high-temperature and ultra-high-pressure heteroepitaxial diamond wafers: Load the above-mentioned synthesis block into the synthesis chamber of the 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 100~180 minutes. The nickel-manganese-cobalt alloy sheets on both sides of the silicon carbide wafer between each two layers of isolation carbon sheets are melted, and the silicon inside the silicon carbide wafer will be integrated into the nickel-manganese-cobalt alloy sheets. 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 will be rearranged in a diamond crystal structure, and finally a diamond wafer is generated. The diamond wafer is taken out of the carbon tube and cooled to room temperature.

2. The method for preparing a diamond wafer from a silicon carbide wafer according to claim 1, Features: The weight percentage of nickel in the nickel-manganese-cobalt alloy sheet 1 and the nickel-manganese-cobalt alloy sheet 2 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 diamond wafer from a silicon carbide wafer according to claim 1, Features: The thickness of the silicon carbide wafer is 0.2-2 mm.

4. The method for preparing a diamond wafer from a silicon carbide wafer according to claim 1, Features: The thickness of the nickel-manganese-cobalt alloy sheet 1 and the nickel-manganese-cobalt alloy sheet 2 are both 0.1-2.

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