Published online by Cambridge University Press: 25 February 2011
For low temperature silicon epitaxy it is not only important to have an oxygen free environment during growth but also an initial silicon surface free of trace concentrations of oxygen, carbon and other impurities. Variations in the pre-clean process (using the standard ex-situ aqueous hydrofluoric acid dip) used for ultra high vacuum chemical vapor depostion (UHVCVD) of silicon, result in interfacial oxygen levels ranging from 2 × 1012atoms/cm2 to 1014atoms/cm2 as measured by secondary ion ion mass spectroscopy (SIMS). Using a dilute Schimmel etch we have delineated the dislocations in the thin silicon epitaxial layers grown by UHVCVD. Correlation of the etch pit density to the interfacial oxygen levels suggests a power law dependence. Plausibility arguments are presented to explain this power law dependence.