The structural evolution of seed surfaces during the initial stages of physical vapor transport SiC growth

The surface evolution of 6H-SiC crystals, treated in an environment similar to conditions that occur during the initial stages of a physical vapor transport growth run, was investigated with optical microscopy and atomic force microscopy (AFM). Seed crystals were heated in a carbon-rich environment, with Ar pressures between 650 torr and 10 torr, for 15 min at temperatures between 1400 degrees C and 2000 degrees C. At an Ar pressure of 650 torr, the temperature threshold for severe surface decomposition was less than 1800 degrees C. AFM images reveal the formation of 0.5 to 2 mu m faceted pits on the terraces and the formation of deposits on macrosteps.