Improvement of microtubule defects of SiC substrate through a thermal effect control method

Silicon carbide, as a third-generation semiconductor, has numerous advantages, such as high-pressure resistance, high-temperature resistance, high-frequency and high-power capabilities, radiation resistance, etc. Due to these properties, it is widely used in the fields of high-power transmission devices and new energy. However, the problem of microtubules needs urgent attention. During the crystal growth process, thermal stress generates microtubules, which results in the formation of hollow screw dislocations with a large Burgess vector, leading to a particular hollow structure. Microtubules greatly affect the performance and lifespan of the device under high voltage and high current conditions. In this paper, we have significantly improved the microtubule defects issue by controlling the thermal field. The diameter of a single microtubule was reduced from 10 μm to 1 μm, and the density of microtubules decreased from 3.98 to 0.8 microtubules/cm². As a result, the quality of silicon carbide crystals has been significantly enhanced.