ANTIPHASE BOUNDARIES IN GAAS-LAYERS ON SI AND GE

A systematic study of the formation of antiphase boundaries and their properties in GaAs layers grown by metalorganic chemical vapor deposit ion (MOCVD) on Si1-xGex/Si (001) and Ge (001) substrates has been perf ormed by chemical etching, scanning and transmission electron microsco py. The main attention is paid to the peculiarities of antiphase bound ary propagation through the epitaxial layer and the interaction of bou ndaries with dislocations. Three various antiphase boundary configurat ions are determined. These experimentall observed configurations are i n good agreement with those deduced from formal analysis of heterostru cture crystal lattice. A connection of the boundary geometric configur ations with the vapor phase composition oscillations in the crystalliz ation zone is proposed. The stable [As]/[Ga] ratio in the vapor phase leads to the annihilation of inclined antiphase boundaries, whereas th e concentration oscillations cause the formation of zigzag-like bounda ries which propagate through the epitaxial layer.