Oxidation of 6H silicon carbide in carbon containing atmosphere

The effect of different oxidizing ambients on the SiC/SiO2 interface has been investigated. We studied the dry oxidation of 6H silicon carbide in O2 with different partial pressures of CO2 as well as in pure CO2 and CO. The density of states at the interface Dit characterized by admittance spectroscopy was found to be correlated with the partial pressure of CO2. We propose that the CO2 partial pressure prevents the outdiffusion of the CO2 which results from the oxidation of SiC leading to a higher Dit with increasing CO2 partial pressure in the oxidizing ambient (Dit (dry O2)=6.3×1010 cm−2 eV−1, Dit(100% CO2)=9.4×1011 cm−2 eV−1).