Growth of ordered SrO layers on Si(100) using metal-organic surface reactions

Abstract

The formation of ordered alkaline earth metal-oxide layers on Si(100) through metal-organic surface reactions has been investigated. Strontium oxide layers were deposited on a thin (1.0±0.2nm) SiO2 layer grown on Si(100) using a saturation coverage of the β-diketonate precursor bis(2,2,6,6-tetramethyl-3,5-heptanedionato)strontium [Sr(thd)2] followed by reaction with H2O. Oxide desorption at high temperatures (>800°C) leads to an ordered strontium layer on the silicon surface. Auger electron spectroscopy, x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, and low-energy electron diffraction have been used to investigate the progress of the reaction. The data show a Sr∕Si(100) surface with 3× order and a Sr coverage of (0.9±0.1)×1014∕cm2. The observed metal coverage and ordering are explained by the saturation of the adsorbed metal-organic layer due to steric interactions that limit the adsorbed coverage. The results are promising for alternative methods to fabricate epitaxial oxides on silicon substrates.