Impurity defect interactions in GaAs

Abstract

Bulk Czochralski (CZ) and vapor phase epitaxy (VPE) layers of n GaAs have been irradiated with 1-MeV electrons, with doses ranging from 2×1015 to 1017 cm−2 and temperatures ranging from 240 to 330 °C. In CZ material, up to seven defects are detected. In VPE layers, five defects are observed. The variation of their introduction rates have been determined versus the temperature of irradiation. This study allows us to show that these traps are complex defects, due to the interaction of arsenic interstitial (IAs) with the impurities contained in the material. The fact that we detected the introduction of traps having the same electrical characteristics as the well-known EL5 and EL2 traps found usually in unirradiated materials provides information on their nature. Finally, a complete compensation of the material can be obtained, which demonstrates the feasibility of producing semi-insulating layers by irradiation.