Silicon Oxidation and Fixed Oxide Charge

Abstract

The oxidation of silicon is described in terms of an ionic transport mechanism. The model includes the effect of internal fields on ionic conduction to explain the hampered growth. A simple power‐parabolic growth law, , is derived for the increase of oxide thickness, , with time, . It has an excellent fit with growth curves for . Hence, there is no need to assume an "initial" regime, as needed in the linear‐parabolic law. The expression includes the linear‐parabolic law as a special case. The "cross‐over" of growth curves of the main orientations is predicted by the model, as well as the magnitude and location of the fixed oxide charge, . Furthermore, the model predicts a semilogarithmic oxygen pressure dependence of , which is indeed observed.