Method for growing silicon carbide crystals by PVT method and device thereof

Abstract

The invention provides a method for growing silicon carbide crystals by a PVT method and a device thereof. The method comprises the following steps: (1) an assembling stage; (2) a heating stage: placing the assembled crucible in a furnace body, heating the crucible, and controlling the temperature difference between the temperature of the center of the top end of the crucible and the temperature of the edge of the top end of the crucible to be delta T1; and (3) a crystal growth stage: keeping the temperature of the center of the top end of the crucible unchanged, controlling the thermal insulation cover to move upwards along the side wall of the thermal insulation cylinder, and controlling the temperature difference between the temperature of the center of the top end of the crucible and the temperature of the edge of the top end of the crucible to be reduced to T2, so that the silicon carbide raw material is conveyed to the seed crystal for crystal growth in a gas phase manner. By controlling the heat preservation cover to move upwards, the annular temperature field is more uniform and stable, and the radial temperature gradient is gradually and slowly reduced to delta T2, so that directional quantitative adjustment of the radial temperature gradient is realized, the radial temperature gradient at the seed crystal is gradually reduced, the difference between the minimum thickness of the center and the minimum thickness of the edge of the silicon carbide crystal is reduced, and the effective utilization rate of the silicon carbide crystal with the same weight is increased.

Description

technical field [0001] The invention relates to a method and a device for growing silicon carbide crystals by a PVT method, belonging to the technical field of semiconductor material preparation. Background technique [0002] Silicon carbide crystal is a typical wide bandgap semiconductor material, and it is one of the representatives of the third generation of semiconductor materials after silicon and gallium arsenide. Silicon carbide crystal has excellent characteristics such as high thermal conductivity, high breakdown field strength, and high saturation electron mobility, and has become one of the popular materials for preparing high-temperature, high-frequency, high-power and radiation-resistant devices. [0003] Currently, silicon carbide growth methods mainly include physical vapor transport (PVT), liquid phase epitaxy (LPE), and chemical vapor deposition (CVD), among which PVT is the most mature method. The PVT method for growing silicon carbide crystal growth furna...

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Problems solved by technology

[0005] In the existing method of raising and lowering the crucible during the crystal growth process, the temperature field at the seed crystal can be adjusted and controlled by adjusting the position of the crucible, but the lifting and lowering of the crucible will also seriously affect the uniformity and stability of the temperature field at the seed crystal. Disrupt the orderly transmission of silicon carbide atmosphere, and cause the silicon carbide powder in the crucible to vibrate and shift, significantly increase the probability of defects such as polymorphism and inclusions, and reduce the crystallization quality of silicon carbide, etc.

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