Implications of a model for instability during film growth for strained InGaAs and SiGe layers

We analyze experiments on the morphology of strained InGaAs and SiGe layers using a nonequilibrium stability analysis. Stability diagrams for growing films as a function of the deposition rate, the temperature and the misfit are calculated and compared to experimental reports. We show that for InGaA s layers, the onset of surface roughening is due to an instability against simultaneous modulations of the surface profile and the composition. For Si Ge, the onset of surface roughening cannot be described by an instability, but rather, is due to a nucleation mechanism. (C) 1999 American Institute o f Physics. [S0003-6951(99)03501-9].