Kinetics of thermal oxidation of 6H silicon carbide in oxygen plus trichloroethylene

Abstract

In this work, the behaviors of the trichloroethylene (TCE) thermal oxidation of 6H silicon carbide (SiC) are investigated. The oxide growth of 6H SiC under different TCE concentrations (ratios of TCE to O2) follows the linear-parabolic oxidation law derived for silicon oxidation by Deal and Grove, J. Appl. Phys., 36 (1965). The oxidation rate with TCE is much higher than that without TCE and strongly depends on the TCE ratio in addition to oxidation temperature and oxidation time. The increase in oxidation rate induced by TCE is between 2.7 and 67% for a TCE ratio of 0.001-0.2 and a temperature of 1000-1150°C. Generally, the oxidation rate increases quickly with the TCE ratio for a TCE ratio less than 0.05 and then gradually saturates for a ratio larger than 0.05. The activation energy EB/A of the TCE oxidation for the TCE ratio range of 0.001-0.2 is 1.04-1.05 eV, which is a little larger than the 1.02 eV of dry oxidation. A two-step model for the TCE oxidation is also proposed to explain the experimental results. The model points out that in the SiC oxidation with TCE, the products (H2O and Cl2) of the reaction between TCE and O2 can speed up the oxidation, and hence, the oxidation rate is highly sensitive to the TCE ratio. © 2005 The Electrochemical Society. All rights reserved.