PHOTOCONDUCTANCE MINORITY-CARRIER LIFETIME VS SURFACE PHOTOVOLTAGE DIFFUSION LENGTH IN SILICON

Recombination lifetime and diffusion length measured with the photoconductance decay and surface photovoltage techniques are compared theoretically and experimentally, and reasons for possible discrepancies are discussed. Specific examples are given which show that, if full advantage of these noncontact and nondestructive procedures is to be taken, it is necessary that surface recombination be considered in the analysis of any experimental data. This is particularly true for samples where the diffusion length is greater than one-fourth of the wafer thickness, a condition for which it is essential that theoretical algorithms for separating the bulk and surface components of recombination be developed.