Correlation of electrolytic-etch and surface-photovoltage techniques for the detection of electrically active defects in silicon

Abstract

Electrically active defects in a 2-μm n-type epitaxial layer on a p-type silicon wafer were mapped using a scanning-surface-photovoltage technique (SSP). The crystal was then subjected to an anodic etch which preferentially attacks electrically active defects, permitting a detailed correlation to be made between defects revealed by the two techniques. Defects visible in the SSP image usually gave rise to etch pits during anodic exposure in HF solution. The results are discussed in terms of the theory of the SSP and anodic-etch techniques.