EVIDENCE FOR INHOMOGENEOUS GROWTH-RATES IN PARTIALLY RELAXED INGAAS INP HETEROSTRUCTURES/

The surface morphology and the dislocation structure of thin and thick strained InxGa1-xAs heterostructures grown on (001) InP substrates ha ve been investigated using atomic force microscopy and transmission el ectron microscopy. Long linear ridges, correlated to underlying disloc ations, are detected in thin partially relaxed In0.82Ga0.18As layers. The ridges (with increased height along the [110] direction comparing to along the [1-10] direction) are associated with strong inhomogeneou s local growth rates induced by elastic strain relief and controlled b y kinetic factors. The crosshatched surface morphology in thick In0.65 Ga0.35As layers is explained using the same mechanism with multiplicat ion and interaction of dislocations and ridges during growth. In contr ast, the development of isolated ''V-shaped'' grooves parallel to [1-1 0] in lattice-matched capping layers grown on partially relaxed In0.82 Ga0.18As quantum wells is explained by the generation of surface corru gations in tensile strained regions appearing just above the elongated relaxed region of In0.82Ga0.18As. (C) 1995 American Institute of Phys ics.