Electron Bombardment Damage in Silicon Esaki Diodes

Abstract

The excess current in silicon Esaki diodes has been shown to be a sensitive indicator of the density and distribution of states intorduced into the forbidden gap by electron bombardment. Both the effects of bombardment and the annealing properties of the radiation damage have been found to depend upon the specific donor in the n-type region of the diode. The average bombardment dose of 1-Mev electron/cm2 needed to increase the excess current density by 1 amp/cm2 at a bias of 0.3 v is 1.2×1016 for P-doped diodes and 0.8×1016 for Sb- or As-doped diodes. Upon annealing in an inert atmosphere, at temperature in the range 300°–400°C, the bombarded diode is restored to its original characteristics. While the annealing studies reveal novel interactions, they show considerable similarity with other work where the radiation damage was monitored by carrier lifetime or conductivity measurements. Structures observed in the I–V characteristics during the annealing indicate that the bombardment-induced levels at Ev+0.27 and Ev+0.06 are due to pairing of a primary defect (probably a vacancy) with an arsenic and a phosphorus impurity atom, respectively.