CORRELATION OF ANISOTROPIC STRAIN RELAXATION WITH SUBSTRATE MISORIENTATION DIRECTION AT INGAAS GAAS(001) INTERFACES/

We have investigated the effects of substrate misorientation towards ( 111)A, (111)B, and (011) on asymmetries in the strain relaxation of In xGa1-x,As, grown on (001) GaAs substrates by molecular beam epitaxy. F or epilayers grown under conditions of two-dimensional growth, we find large anisotropies in bulk strain relaxation and epilayer rotation ab out an in-plane axis (epilayer tilt) in proportion to the degree of (1 11)A misorientation. The residual strain asymmetry is largest for the (111)A misoriented substrate (>50%) and smallest for the (111)B misori ented substrate (<15%). At higher growth temperatures, the bulk strain relaxation becomes isotropic while the epilayer tilt remains sensitiv e to the offcut direction. At all temperatures, a preference for epila yer tilt toward the [110] direction for (011) misorientations is obser ved. (C) 1995 American Institute of Physics.