In situ laser light scattering studies on the influence of kinetics on surface morphology during growth of In0.2Ga0.8As/GaAs

Abstract

Using real-time in situ laser light scattering we study, in this work, the influence of growth kinetics on the initial development of the crosshatched morphology and its subsequent evolution. The crosshatched morphology is characteristic of relaxed low strained layers (ε< 2%) and has been traditionally related to the plastic relaxation process driven by generation and multiplication of dislocations. However we have observed that, if the growth rate is slow enough, the onset of crosshatch formation takes place at a layer thickness in which the dislocation formation and multiplication processes have not appeared yet. This reveals that the stress field generated by the small density of misfit dislocations formed by bending of the dislocations preexisting in the substrate is strong enough to affect the evolution of the growth front morphology. Our results also show that the starting point and evolution of this characteristic morphology depend on the growth rate in such a way that when the growth rate is lower the crosshatched morphology starts to develop at a smaller thickness and shows a faster evolution rate.