Change of Surface and Electrical Characteristics of Silicon Wafer by Wet Etching(2) - Relationship between Surface Roughness and Electrical Properties -

Abstract

The relationship the between electrical properties and surface roughness (Ra) of a wet-etched silicon wafer were studied. Ra was measured by an alpha-step process and atomic force microscopy (AFM) while varying the measuring range <TEX>$10{\times}10$</TEX>, <TEX>$40{\times}40$</TEX>, and <TEX>$1000{\times}1000{\mu}m$</TEX>. The resistivity was measured by assessing the surface resistance using a four-point probe method. The relationship between the resistivity and Ra was explained in terms of the surface roughness. The minimum error value between the experimental and theoretical resistivities was 4.23% when the Ra was in a range of <TEX>$10{\times}10{\mu}m$</TEX> according to AFM measurement. The maximum error value was 14.09% when the Ra was in a range of <TEX>$40{\times}40{\mu}m$</TEX> according to AFM measurement. Thus, the resistivity could be estimated when the Ra was in a narrow range.