Oxygen Incorporation Mechanism during Atomic Layer Deposition of Al2O3 onto H-Passivated Si(100)-2×1

Abstract

Using electronic structure calculations, a new oxygen incorporation mechanism is predicted for the atomic layer deposition of Al2O3 from trimethylaluminum (TMA) and H2O. During the TMA exposure, trace amounts of H2O can react with the H/Si(100) surface to form a surface hydroxyl group through a mechanism involving the coadsorbed reactants (TMA and H2O). As compared to the isolated H2O + H/Si(100) reaction, the H2O + TMA + H/Si(100) reaction is strongly preferred both kinetically and thermodynamically. This reaction is relevant to the formation of the SiO2 interfacial oxide layer, which is an unwanted feature produced during the deposition process.