New results on low-temperature thermal oxidation of silicon

Abstract

The commonly accepted linear-parabolic oxidation model for the thermal oxidation of Si includes two rate processes in the steady state: a reaction between Si and oxidant at the Si-SiO2, interface and transport of oxidant through the SiO2, film. Based on available data, it is argued that the former process seems dominant for thin-film growth in dry O2. A number of measured SiO2, film and Si-SiO2, interface properties are reported, as well as the variation of the these properties with oxidation temperature and Si substrate orientation. These properties include refractive index, density, intrinsic stress, interface fixed oxide charge and interface trapped charge. It is also observed that all of these properties display similar oxidation-temperature and inert-anneal behaviour together with a complex orientation dependence. Through the use of a modified form for the interface reaction, a better understanding is obtained of both the origin of these measured properties, and of new oxidation data taken on five Si orientations and at lower oxidation temperatures than previously reported.