Anomalous oxidation rate in 6H-SiC depending on the partial pressure of O₂ and H₂O

Abstract

On the thermal oxidation of silicon carbide, the partial pressure of H₂O affects the oxidation rate very differently from silicon. We have found that the oxide thickness shows the bell-shape as the function of the relative partial pressure of H₂O, called the p parameter. The main reason for this is that the diffusion limiting process diminishes according to the reduction of p while the linear rate constant does not depend on p strongly until p=0.15. The reduction of the oxide thickness below p=0.15 is explained by the abrupt reduction of the linear rate constant. In addition, the interface quality for oxides grown in the different p has been investigated. For the reduction of the surface states, the large p (over p=0.8) is favorable.