Annealing and defect characterization of semi-insulating GaAs crystals

摘要

GaAs cubic samples and wafers were two-step annealed in order to investigate arsenic precipitate dissolutions and conversions to p-type conductivity. Spatial differences in the arsenic vapour composition due to temperature gradients along the wafers during cooling down apparently contribute to the observed mm- range non-uniformities of the conductivity type. The microscale uniformity is higher in the p-type areas than in the central semi-insulating region of the wafers. The transition regions between the areas of different conductivity types exhibit a very interesting structure. These results are based on etching experiments and electrical and optical characterization methods.