Excess Surface Currents on Germanium and Silicon Diodes

Abstract

The investigation of excess currents on silicon and germanium diodes has shown that inversion layers give an approximate logarithmic increase of excess current with applied voltage. Approximately ohmic excess currents are observed not only in the presence of water vapor but also in the presence of vapors of certain organic liquids. These excess currents can be shown to be due to a surface conductance which has a different bias voltage dependence from that exhibited by inversion layers. Evidence is presented which indicates that the holes induced in the liquid film (outer surface states) move in an applied field much like holes in a molten semiconductor, provided the liquid film is coherent. This added conductance is responsible for the ohmic behavior in the presence of condensable vapors.