HCl addition to an oxidiing ambient during thermal oxidation of silicon can prevent the generation of oxidation‐induced stacking faults in the crystal during the subsequent standard thermal‐oxidation cycles. The gettering action of stacking‐fault nuclei from the surface regions of the silicon wafers is induced under appropriate HCl oxidation conditions (temperatures, times, and HCl concentrations). Conditions for an undesirable etching of the silicon surface are also presented. These two phenomena presumably occur when certain concentrations of a chlorine species are incorporated near the silicon–silicon dioxide interface.