Evaluation of mechanical damage by high resolution x-ray diffraction and minority carrier recombination lifetime in silicon wafer

Abstract

In Czochralski silicon wafers, the effect of mechanical back side damage was systematically analyzed by x-ray diffuse scattering and minority carrier recombination lifetime measurements. X-ray section topography and wet oxidation/preferential etch methods were also employed. A liquid honing method was used to induce mechanical damage, and the damage grade was varied by controlling process parameters. A high resolution x-ray analysis of the samples was carried out before and after heat treatment at 1100 °C for 60 min. The magnitude of diffuse scattering was analyzed quantitatively by integrating the excess intensity of diffuse scattering into a reciprocal space map and its correlation with the mechanical damage was examined. As the grade of mechanical damage increased, the degree of diffuse scattering increases and minority carrier recombination lifetime decreases, suggesting the generation of more defects. We discuss other experimental results from the viewpoint of the structure–property relationship.