The defects induced in the Si substrate by a CHF3/Ar plasma dry etch of SiO2on Si were studied by correlating the reactive ion etching (RIE) induced changes in the minority‐carrier bulk lifetime and surface recombination velocity with the data on damage obtained by the capacitance–voltage (C–V) and current–voltage (I–V) characteristics. Wet etched control samples were used to distinguish the defects induced by the processing in itself from the RIE‐induced defects. The influence of rf power was studied. No damage or contamination of the Si substrate was detected; a modification of the surface electric properties was observed in the samples etched at low rf power, and attributed to the presence of a residue layer.