During a study of the homoepitaxial growth of Si on Si(111), we have found that stacking‐fault densities in the deposited Si films decreased by two to three orders of magnitude above a ’’critical’’ substrate deposition temperature, 1250 °C. Nucleation of stacking faults in the deposited films is correlated, via SEM observations and infrared absorption measurements, with the presence of SiC protuberances on the substrate surface. We propose a simple model for SiC cluster growth (and decay) which explains the rapid decrease with temperature of the amount of SiC formed on the Si surface.