Polytype Change of Silicon Carbide at High Temperatures

Abstract

Thermal stability of single crystalline 3C-SiC was investigated at temperatures ranging from 1800°C to 2400°C in an Ar atmosphere. Polytype change from the cubic 3C modification to the hexagonal 6H modification was observed. Single crystalline 3C-SiC (100) ~300μm thick and 3C-SiC (100) films (~10 μm thick) grown on Si (100) were used after removing Si in a HF+HNO₃ mixture. Experiments were carried out with various parameters of annealing temperature, pressure and time. Polytypes and crystallographical planes of annealed samples were examined by photoluminescence measurements, X-ray diffraction and RHEED analyses. The effect of annealing on the variation in the Si/C composition ratio of annealed samples was determined by Auger electron analysis.