SiO Desorption Kinetics of Si(111) Surface Oxidation Studied by Real-Time Photoelectron Spectroscopy

Abstract

The kinetics of the initial oxide growth on the Si(111) surface have been investigated using real-time photoelectron spectroscopy and density functional theory (DFT) calculations. Including SiO desorption into the description of the transition from Langmuir-type adsorption to two-dimensional (2D) oxide island growth reveals that oxidation at high temperature T and low oxygen pressure P_O2 is not governed by 2D oxide island growth despite sigmoidal oxygen uptake curves. Because SiO desorption during the initial oxide growth depends strongly on temperature and oxide coverage θ_oxide in the transition region, an initial oxidation model for the transition region is proposed. According to P_O2-dependent experimental results and theoretical calculations, the frequent occurrence of SiO desorption is due to the formation of the transition state tri-ins×2 species, SiO desorption during the initial oxidation is suppressed by the most thermally stable oxygen adsorption species tri-ins×3 formed on Si(111)7×7. [DOI: 10.1380/ejssnt.2013.116]