EFFECT OF VARIOUS FACTORS UPON THE STOICHIOMETRY OF GAAS HOMOEPITAXIAL LAYERS GROWN BY LPE

The effect of Sn doping and orientation of the substrate surface on va lue and distribution of lattice period and photoluminescence over and within homoepitaxial GaAs layers are studied. It is shown that the pre dominant type of native defects is the As vacancy (V(As)) in the epila yers grown on (111)A oriented substrate, and a large concentration of interstitial atoms is present in (111)B epilayers side by side with V( As). The difference of the native defect state in differently oriented epilayers is the fundamental cause of the different behaviour of epil ayers in the process of subsequent annealing in H-2 flow.