Real-time observation of the dry oxidation of the Si(100) surface with ambient pressure x-ray photoelectron spectroscopy

We have applied ambient-pressure x-ray photoelectron spectroscopy with Si 2p chemical shifts to study the real-time dry oxidation of Si(100), using pressures in the range of 0.01–1Torr and temperatures of 300–530°C, and examining the oxide thickness range from 0to∼25Å. The oxidation rate is initially very high (with rates of up to ∼225Å∕h) and then, after a certain initial thickness of the oxide in the range of 6–22Å is formed, decreases to a slow state (with rates of ∼1.5–4.0Å∕h). Neither the rapid nor the slow regime is explained by the standard Deal-Grove model for Si oxidation.