Channeling and diffusion in dry-etch damage

Abstract

At present channeling is accepted to be the primary mechanism causing defects deep within dry-etched material, with diffusion possibly modifying the final defect distribution. In this article detailed analytic expressions are presented incorporating both these mechanisms. The dominant parameter affecting damage depth is found to be the mean channeling length. We show how enhanced diffusion, e.g., by illumination, may increase the observed damage. We also study the effect of damage on depletion depths and suggest how the channeling length may be inferred from the etch-depth dependence of conductance or Raman spectroscopy measurements.