Ultrahigh Quality Silicon Carbide Single Crystals

We have succeeded in achieving the growth of ultrahigh quality silicon carbide (SiC) single crystals using a repeated a-face (RAF) growth method. The crystal quality of conventional SiC substrates, in which a large density of crystalline defects are present, is one of the biggest problems that has hampered the realization of high-performance SiC-based electric devices that can simultaneously satisfy requirements such as high-power, high-reliability, and low-loss characteristics. We have proposed a novel method, a RAF growth method, which effectively reduces crystal defects and has realized world-first high-quality SiC crystals without micropipe defects (referred to as killer defects), in addition to obtaining a lower density of dislocations (by two to three orders than those of conventional-quality SiC substrates) by which crystalline lattice distortion can be completely removed. These results were published in the journal Nature in 2004.