Kinetics of thermal oxidation of silicon

Abstract This article reviews findings from the 2000s that led to a reevaluation of the conventional understanding of silicon thermal oxidation, prompted by the discovery of the so-called layer-by-layer oxidation phenomenon in the 1990s. Since the seminal work of Deal and Grove, silicon thermal oxidation has been described by a two-step model: an initial linear regime limited by interfacial reactions, followed by a parabolic regime governed by the diffusion of oxidant molecules. In 2003, however, it was demonstrated that layer-by-layer oxidation could be reproduced by a simple diffusion-limited process. Moreover, first-principles calculations have revealed that the energy barrier for interfacial oxidation with O 2 molecules is negligible. These findings underscore the need to revise the conventional Deal-Grove model, particularly in the context of dry oxidation. In this article, a linear-parabolic equation, similar to the Deal–Grove equation, is derived by assuming an increase in the diffusion barrier of oxidant molecules within a compressively stressed SiO 2 region, known as the structural transition region, near the interface. The proposed model not only reshapes the interpretation of the linear-parabolic growth behavior but also calls for a reconsideration of the anomalously rapid initial growth observed in dry oxidation. Portions of this article are adapted from a Japanese publication (T. Watanabe, Kinetics of Silicon Oxidation, to be published in Thermal Oxidation of Si, SiC and Related Semiconductors , Chapter 10, The Japan Society of Applied Physics, Kindai-kagakusha Co., Ltd., (2026) [in Japanese]).