Published online by Cambridge University Press: 10 February 2011
Wet and dry oxidations of polycrystalline SixGe1-x, with various compositions have been studied at different temperatures. The growth rate of SiO2 is found to be enhanced by Ge, and the enhancement effect is more pronounced in H2O than in O2. A mathematical model, which assumes simultaneous oxidation of Si and Ge and reduction of GeO2 by free Si available at the growing-oxide/SixGe1-x interface, is found to give a quantitative description of the SiO2 growth during thermal oxidation of SixGe1-x. Kinetic parameters are extracted by comparing the model with experiments. The linear and parabolic rate constants for Si oxidation are determined on control Si (100) wafers and polycrystalline Si films. Simple expressions are used for the interdiffusion of Si and Ge in SixGe1-x. For wet oxidation, the activation energy for the reaction rate constant of Ge oxidation is found to be smaller than that of Si oxidation.