STUDY OF THE ELECTRICAL ACTIVE DEFECTS INDUCED BY REACTIVE ION ETCHING IN N-TYPE SILICON

The defects induced in the Si substrate by a CHF3/Ar plasma dry etch of SiO2 on 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 RTE-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.