Transmission electron microscopy study of microdefects in dislocation-free GaAs and InP crystals

Abstract
The transmission electron microscopy study has been carried out to characterize the structural defects in heavily impurity‐doped LEC‐grown GaAs and InP crystals which are free from native dislocations. The microdefects in S‐ and Te‐doped GaAs crystals were found to be mainly Frank‐type stacking faults and prismatic dislocation loops. Diffraction contrast analysis revealed that all the microdefects were of interstitial type. However, in Zn‐doped GaAs and Zn‐, S‐, and Te‐doped InP crystals, the microdefects were hardly observed, which suggests that those crystals could be useful substrates for electronic devices. The appearance, especially in GaAs : S, of microdefects and also of helical dislocations associated with the effects of impurities on reducing dislocations are discussed.