Phase diagram for the interaction of oxygen with SiC

We report on experimental studies of the interactions of oxygen with the 4H– and 6H–SiC surfaces at high temperatures. It is observed that these interactions lead to the growth of passivating SiO2 layers at high O2 pressures, etching of the surfaces at lower pressures, and enhancements of the surface segregation of carbon at still lower pressures. A pressure–temperature phase diagram for the oxidation of SiC containing these three experimentally observed regions is presented.