Effect of carbon concentration on the thermal conversion of liquid-encapsulated Czochralski semi-insulating GaAs

Abstract

Thermal conversion of liquid‐encapsulated Czochralski semi‐insulating GaAs crystals with various carbon concentration are investigated by measuring carrier concentration depth profiles after vacuum annealing. In case of high carbon concentration, the carrier concentration in the near surface region corresponds to the residual carbon concentration. In case of low carbon concentration, however, it is found that the As vacancy related acceptor is diffused from the surface. These results suggest that p conversion is caused not only by the reduction of EL2 concentration in the surface region, but also the thermal induction of the native acceptor.