Effects of In impurity on the dynamic behavior of dislocations in GaAs

The effects of In impurity on the dynamic behavior of dislocations in GaAs crystals are investigated in comparison with those of Si impurity. Indium, even at a concentration of the order of 1020 cm−3, is found to affect the velocity of moving dislocations only slightly while Si impurity at a concentration of the order of 1018 cm−3 reduces it by one or two orders of magnitude. However, α dislocations are easily immobilized by In atoms while they are at rest by gettering the latter. Immobilization of β dislocations due to In gettering is much weaker than that of α dislocations. An interpretation is given of how such a difference in locking by In impurity comes about between α and β dislocations. The function of Si impurity to lock both α and β dislocations is stronger than that of In impurity on α dislocations. Nevertheless, the locking effect due to Si impurity manifests itself only in the high-temperature range. This seems to be related to the low diffusivity of Si impurity in GaAs crystals.