Stability-instability transition of reaction fronts in thermal oxidation of silicon

Abstract

By combining atomic force microscopy and x-ray reflectivity measurements, the morphological evolution at the SiO 2 / Si͑001͒ interface during thermal silicon oxidation was systematically studied as a function of oxidation temperatures. We found that the oxidation-induced roughening switches to smoothening at an oxidation temperature of 1250°C on the oxidation front. The transition is governed by how the strain induced by oxidation is spatially relieved at the interfaces in the silicon oxide bulk film through the interfacial transition layers, which is inevitably important for the strain-relief mechanism.

Real-Time Analyses of Strain in Ultrathin Silicon Nanolayers on Insulators during Thermal Oxidation

“…This means that the intrinsic strain induced by the thermal oxidation at the interface immediately relaxes normal to the surface during the real-time measurement. However, we have to keep in mind that there exists interfacial transition layers at the interface between the Si and thermal oxide SiO 2 film even at such high temperatures, 13) which means that the there exists small in-plane strain at the growing interfaces between the silicon nanolayers and SiO 2 . Therefore, the most plausible origin is the intrinsic strain induced by thermal oxidation at the interfaces between the silicon nanolayers and thermal silicon oxide films and/or buried oxide films.…”