OXYGEN INCORPORATION DURING LOW-TEMPERATURE CHEMICAL-VAPOR-DEPOSITIONGROWTH OF EPITAXIAL SILICON FILMS

We have studied the incorporation kinetics of oxygen during the chemic al vapor deposition (CVD) growth of epitaxial silicon and silicon-germ anium layers at temperatures between 700 and 750-degrees-C. In this te mperature range, the incorporation of oxygen into the growing film is a kinetically driven process and is not governed by equilibrium condit ions. Oxygen concentrations exceeding the solid solubility for interst itial oxygen in silicon can be incorporated into the epitaxial layers. We determine an effective sticking probability for oxygen on the surf ace of silicon under CVD growth conditions and find it to be 100 times lower than that found in ultrahigh vacuum experiments. This reduction in sticking is due to both hydrogen surface coverage and boundary lay er effects. We also have determined the maximum oxygen contamination l evel allowed in the gas stream for the CVD growth of low oxygen conten t silicon films.