Bulk Homogeneous Uniaxial Stress Arising from Surface Damage of Crystalline Silicon and Germanium

Abstract

Abrasion of two opposing surfaces of either crystalline Si or Ge produces a compressive, homogeneous, uniaxial stress extending throughout the bulk perpendicular to the surfaces. This is concluded by analyzing the splittings, intensities, and polarizations of the sharp Lyman absorption lines of bulk shallow impurities in the abraded materials. This effect so far has been observed for samples of thickness, t, from 0.4 to 5 mm for Si ground with water slurries of SiC or alumina with optical faces coplanar with {100} and {111} planes while {100}, {110}, {111}, and {112} planes of Ge have been abraded with SiC in water and examined over the range 0.8 ≤ t ≤ 3.0 mm. For both materials, the internal stress is found to be inversely proportional to t. Controlled etching indicates the damaged layers producing the bulk stress to be < 0.5 μm thick.