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CN-224227290-U - Silicon carbide composite seed crystal and silicon carbide seed crystal assembly

CN224227290UCN 224227290 UCN224227290 UCN 224227290UCN-224227290-U

Abstract

The utility model discloses a silicon carbide composite seed crystal and a silicon carbide seed crystal assembly, wherein the silicon carbide composite seed crystal comprises a heat dissipation substrate, a transition layer and a silicon carbide seed crystal, the transition layer is arranged on the heat dissipation substrate, the silicon carbide seed crystal is arranged on one side of the transition layer far away from the heat dissipation substrate, the heat conductivity of the transition layer is larger than that of the silicon carbide seed crystal, and the heat conductivity of the transition layer is smaller than that of the heat dissipation substrate. The silicon carbide composite seed crystal provided by the utility model has the advantages that the transition layer is used as the thermal stress buffer layer, so that interfacial cracks or peeling caused by the difference of thermal expansion coefficients are reduced, and the heat at the silicon carbide seed crystal can be quickly transferred out along the vertical direction and the horizontal direction by establishing the temperature gradient of the high-heat-conductivity radiating substrate, the low-heat-conductivity transition layer and the lower-heat-conductivity silicon carbide seed crystal, so that the larger temperature gradient along the vertical direction and the horizontal direction is realized on the silicon carbide composite seed crystal.

Inventors

  • ZHOU GUOQING

Assignees

  • 江苏第三代半导体研究院有限公司

Dates

Publication Date
20260512
Application Date
20250427

Claims (10)

  1. 1. A silicon carbide composite seed crystal, comprising: A heat-dissipating substrate; the transition layer is arranged on the heat dissipation substrate; The silicon carbide seed crystal is arranged on one side of the transition layer, which is far away from the heat dissipation substrate; The thermal conductivity of the transition layer is larger than that of the silicon carbide seed crystal, and the thermal conductivity of the transition layer is smaller than that of the radiating substrate.
  2. 2. The silicon carbide composite seed crystal according to claim 1, wherein, The silicon surface of the transition layer is provided with a plurality of first groove micro-channels, and the silicon surface of the silicon carbide seed crystal is provided with first bulge micro-channels corresponding to the first groove micro-channels one by one.
  3. 3. The silicon carbide composite seed crystal according to claim 2, wherein, The width of the first groove micro-channel is 5-10 mu m; and/or the depth of the first groove micro-channel is 30-50 μm; And/or the transverse spacing of the first groove micro-channel is 5-10 mm; And/or all the first groove micro-channels are sequentially communicated end to end and are spirally distributed.
  4. 4. A silicon carbide composite seed crystal according to any of claims 1 to 3, wherein, The silicon surface of the silicon carbide seed crystal is provided with a plurality of second groove micro-channels, and the silicon surface of the transition layer is provided with second bulge micro-channels corresponding to the second groove micro-channels one by one.
  5. 5. The silicon carbide composite seed crystal according to claim 4, wherein the silicon carbide composite seed crystal is, The width of the second groove micro-channel is 5-10 mu m; and/or the depth of the second groove micro-channel is 30-50 μm; And/or the transverse spacing of the second groove micro-channel is 5-10 mm; and/or all the second groove micro-channels are sequentially communicated end to end and are spirally distributed.
  6. 6. The silicon carbide composite seed crystal according to claim 1, wherein, The heat dissipation substrate is a diamond substrate, and the transition layer is a silicon carbide transition layer; The surface of the diamond substrate is combined with the carbon surface of the silicon carbide transition layer, the silicon surface of the silicon carbide transition layer is combined with the silicon surface of the silicon carbide seed crystal, and the crystal form of the silicon carbide material in the silicon carbide transition layer is different from that of the silicon carbide material in the silicon carbide seed crystal.
  7. 7. A silicon carbide composite seed crystal according to claim 1 or 6, wherein, The heat dissipation substrate is monocrystalline diamond or polycrystalline diamond; and/or the thickness of the heat dissipation substrate is 300-500 mu m; And/or the thickness of the heat dissipation substrate is less than or equal to two thirds of the thickness of the silicon carbide composite seed crystal, and the thickness of the heat dissipation substrate is greater than or equal to one half of the thickness of the silicon carbide composite seed crystal; And/or the surface roughness of the heat dissipation substrate is smaller than a first preset roughness, wherein the value range of the first preset roughness is 1-5 nm.
  8. 8. The silicon carbide composite seed crystal according to claim 6, wherein, The crystal form of the silicon carbide material in the silicon carbide transition layer is a 3C, 4H, 6H or 15R crystal form; and/or the thickness of the silicon carbide transition layer is 10-50 mu m; And/or the surface roughness of the silicon surface of the silicon carbide transition layer is smaller than a second preset roughness, wherein the value range of the second preset roughness is 1-5 nm; And/or, the silicon carbide transition layer is formed by epitaxial growth or heterobonding.
  9. 9. The silicon carbide composite seed crystal according to claim 6, wherein, The crystal form of the silicon carbide material in the silicon carbide seed crystal is a 3C, 4H, 6H or 15R crystal form; And/or the thickness of the silicon carbide seed crystal is 100-200 mu m; And/or the thickness of the silicon carbide seed crystal is less than one third of the thickness of the silicon carbide composite seed crystal; And/or, the silicon carbide seed crystal is formed by epitaxial growth or heterobonding.
  10. 10. A silicon carbide seed crystal assembly, comprising: A silicon carbide seed holder; a silicon carbide composite seed crystal according to any of claims 1 to 9; And the bonding layer is arranged between the silicon carbide seed crystal holder and the heat dissipation substrate in the silicon carbide composite seed crystal and is used for bonding the silicon carbide composite seed crystal on the silicon carbide seed crystal holder.

Description

Silicon carbide composite seed crystal and silicon carbide seed crystal assembly Technical Field The utility model relates to the field of semiconductor material preparation, in particular to a silicon carbide composite seed crystal and a silicon carbide seed crystal assembly comprising the silicon carbide composite seed crystal. Background The silicon carbide crystal material is widely applied to the fields of electric automobiles, photovoltaics, radio frequency communication and the like due to the characteristics of wide forbidden bandwidth, high thermal conductivity and high breakdown field strength, and is one of the most important third-generation semiconductor materials. Because silicon carbide crystals have very high optical refractive index and high thermal conductivity, the silicon carbide crystals have been used as optical wafers on augmented reality (AR (Augmented Reality, augmented reality) glasses at present, and have very broad market application prospects. The silicon carbide crystal generally realizes massive crystals for large-size commercial application through PVT (PhysicalVapor Transport, physical vapor deposition) and LPE (Liquid Phase Epitaxy, cosolvent liquid phase method), but the growth speed is far lower than that of silicon crystals, at present, the silicon carbide crystal is mainly a crystal with two specifications of 6 inches and 8 inches in diameter, the single crystal growth period is about 7-10 days, the growth speed is extremely slow, the growth speed of most manufacturers in China is 100-150 micrometers per hour, the crystal thickness is only 20-25 mm, the yield is far lower than that of mature monocrystalline silicon, the black box operation in the growth process and the crystal ingot are opaque, and the quality cannot be fed back in time. The company Wolfspeed in the united states grows 8 inch ingots in batches, the growth rate of silicon carbide substrates is higher than 300 micrometers per hour, the thickness is 60mm, and the silicon carbide substrates are at the world leading level. The reason for the slow growth speed of the silicon carbide crystal is that the physical properties of the silicon carbide seed crystal for growth by a physical vapor deposition method or a cosolvent liquid phase method are poor, the traditional seed crystal is composed of a silicon carbide single crystal material with a certain thickness, the thermal conductivity of the silicon carbide single crystal material is only 490W/(m.K), factors influencing the thermal conductivity of the silicon carbide single crystal include impurities, crystal structure defects and the like, for example, the increase of the nitrogen content of the impurities can reduce the thermal conductivity of the material, and the existence of the crystal structure defects can lead to the reduction of the thermal conductivity. The temperature gradient is an inherent driving force of single crystal crystallization during the crystal growth process, and is a key factor determining the crystal growth speed, the crystal growth speed has close positive correlation with the temperature gradient, and the crystal crystallization speed is high under a large temperature gradient, and vice versa. The low thermal conductivity of silicon carbide is unfavorable for forming large vertical temperature gradient required by growth of silicon carbide crystal, so that the growth speed of the silicon carbide crystal is low, the crystal thickness is small, namely the silicon carbide crystal is not thick, the general thickness is only 20-25 mm, or the internal quality of the silicon carbide crystal is poor under the condition of long and thick, and the electronic grade silicon carbide crystal cannot be obtained. Disclosure of Invention The utility model aims to provide a silicon carbide composite seed crystal and a silicon carbide seed crystal assembly, which are used for solving the problems that the low thermal conductivity of a silicon carbide material is not beneficial to the formation of a silicon carbide crystal, the large temperature gradient in the vertical direction is required, the growth speed of the silicon carbide crystal is low, the growth thickness of the silicon carbide crystal is very small, namely, the growth thickness of the silicon carbide crystal is not thick, generally only 20-25 mm, or the internal quality of the silicon carbide crystal is poor under the condition of the growth thickness, and the electronic grade silicon carbide crystal cannot be obtained. In order to achieve the above purpose, the present utility model adopts the following technical scheme: in a first aspect of the present utility model, there is provided a silicon carbide composite seed crystal comprising: A heat-dissipating substrate; the transition layer is arranged on the heat dissipation substrate; The silicon carbide seed crystal is arranged on one side of the transition layer, which is far away from the heat dissipation substrate; The thermal conduc