Effect of electron irradiation on characteristics of Mo Schottky barriers on epitaxial silicon

Abstract

The results of studies on influence of 6 MeV electron irradiation on avalanche breakdown voltage ( U b) and on forward voltage ( U F) at different values of direct current ( I F) for the Mo Schottky diodes on epitaxial silicon of n-type conductivity are presented. It was found out that the avalanche breakdown voltage of the diodes is very sensitive to electron irradiation. A decrease in U b was observed after electron irradiation with a fluence as low as 1 × 10 11 cm −2. An increase in electron irradiation fluence from 1 × 10 11 cm −2 to 5 × 10 14 cm −2 resulted in 30% decrease in U b, however, further increase in electron irradiation fluence from 5 × 10 14 cm −2 to 3 × 10 16 cm −2 led to some increase in the avalanche breakdown voltage. Monotonic increases in U F values at different I F with the increase in electron irradiation fluence were observed starting from a fluence of 5 × 10 14 cm −2. Radiation-induced changes in U b were unstable at room temperature and a significant recovery of U b occurred after maintaining the irradiated diodes at room temperature for 30 days. Annealing at 120 °C for 20 min resulted in the almost complete recovery of U b. Radiation-induced changes in U F values were stable up to 300 °C. Mechanisms of the observed radiation-induced changes in the U b and U F values and defects responsible for the changes are discussed.