Thermal oxidation kinetics of an Si 1− xC x alloy layer ( x ≃ 0.1) on Si(0 0 1) surfaces monitored in real time by RHEED combined with AES

Abstract

To clarify the oxide growth mechanism on strained Si surfaces, the thermal oxidation reaction kinetics of an Si 1− x C x ( x ≃ 0.1) alloy layer with a c(4 × 4) structure grown on Si(0 0 1) surfaces by carbonization with ethylene 636 °C was investigated using RHEED combined with AES. Upon staring the oxidation of the Si 1−xC x ( x ≃ 0.1) alloy layer under the conditions of Langmuir-type adsorption at 383 °C, oxide growth rate is ∼70% higher than that on a clean Si(0 0 1)2 × 1 surface and then decreases considerably corresponding to the decrease of the c(4 × 4) structure. When the Si 1− x C x ( x ≃ 0.1) alloy layer is oxidized under the conditions of two-dimensional oxide island growth with SiO desorption at 690 °C, the initial sticking probability of O 2 molecules measured by the etching rate of a Si surface is ∼26% smaller than that on the clean Si(0 0 1)2 × 1 surface independent of oxide coverage. The temperature dependent changes of initial sticking probability and surface structure are discussed in terms of the intrinsic and thermal strain of the Si 1− x C x ( x ≃ 0.1) alloy layer.