Some New Perspectives on Oxidation of Silicon Carbide and Silicon Nitride


  • J. L. Smialek—contributing editor

  • Presented at the 91st Annual Meeting of the American Ceramic Society, Indianapolis, IN, Apr. 24, 1989 (Engineering Ceramics Division, Paper No. 3-JII-89).


This study provides new perspectives on why the oxidation rates of silicon carbide and silicon nitride are lower than those of silicon and on the conditions under which gas bubbles can form on them. The effects on oxidation of various rate-limiting steps are evaluated by considering the partial pressure gradients of various species, such as O2, CO, and N2. Also calculated are the parabolic rate constants for the situations when the rates are controlled by oxygen and/or carbon monoxide (or nitrogen) diffusion. These considerations indicate that the oxidation of silicon carbide and silicon nitride should be mixed controlled, influenced both by an interface reaction and diffusion.