This article reviews our present understanding of silicon oxidation kinetics in the ultrathin-film regime. Experimental results obtained at the onset of oxidation at room temperature, low temperatures and high temperatures are divided into two phases. In the incubation phase observed at the onset of oxidation, the oxide does not grow. Following the incubation phase, the oxide growth phase begins. Modeling the incubation phase and the growth phase are then described and correlated. A model consistent with both sets of observations is introduced. This model considers the role of silicon-monoxide molecules and silicon self-vacancies in the incubation and growth phases. (C) 1997 Published by Elsevier Science Ltd.