RELAXATION BEHAVIOR OF UNDOPED INXGA1-XP 0.5-LESS-THAN-X-LESS-THAN-0.7 GROWN ON GAAS BY ATOMIC LAYER MOLECULAR-BEAM EPITAXY

We present a study of the relaxation behavior of compressive InxGa1-xP layers grown by atomic layer molecular-beam epitaxy at T-s=420 degree s C with x=56%+/-3% and n=67%+/-3%. Similar (thickness and composition ) InxGa1-xP layers were grown under different growth conditions in ord er to assess the influence of the stoichiometry of the growth front on the structural properties and the relaxation process of this material system. All InxGa1-xP layers were characterized by double-crystal x-r ay diffraction, transmission electron microscopy, and Nomarski interfe rence. Our results show that surface stoichiometry during growth does not affect the relaxation behavior of InxGa1-xP layers but strongly de termines their structural characteristics related to composition modul ation features which appear in all our InxGa1-xP layers. We have estab lished an empirical relation between residual strain and thickness. Th is relation makes predictable the residual strain of more complicated structures which can be introduced as buffer layers in lattice-mismatc hed heteroepitaxial systems. (C) 1996 American Institute of Physics.