Measurement of Germanium Surface States by Pulsed Channel Effect

Abstract

Densities, cross sections, and activation energies of several fast germanium surface states are inferred from low-temperature conductivity relaxations in a thin diffused surface layer. Relaxations are induced by application of a sudden reverse biasing pulse. The observed rate of change of channel conductance as a function of temperature is analyzed in terms of a model wherein the equilibrium surface Fermi level is presumed to remain in close proximity to a trap level. The results indicate the existence of an electron trap 0.24 ev from the conduction band and two hole traps 0.17 ev and 0.22 ev from the valence band.