Effects of thermal annealing on the electrical properties of large diameter semi-insulating gallium arsenide

In this paper, the effects of thermal annealing on the electrical parameters in semi-insulating gallium arsenide (SI-GaAs) at 1200 and 1400 K under vacuum conditions were studied. It was found that the electrical parameters of SI-GaAs crystal change with thermal annealing in comparison with as-grown samples. The conductive type changes from n-type to p-type; the Hall mobility and the resistivity decrease, while the carrier concentration increases dramatically. The phenomenon was considered to be associated with the evaporation of arsenic (As) on surface of the sample and the out-diffusion of As interstitial atoms. The related formation mechanisms were also discussed.