HOMOGENEOUS NUCLEATION OF MISFIT DISLOCATIONS IN STRAINED LAYERS

Abstract

The mechanism of strain relaxation by homogeneous nucleation of misfit dislocations from the interface in strained layers has been investigated. Transmission electron microscopy examination in a coherently strained GaInAsP/GaInP heterostructure demonstrated that the critical thickness of the strained layer for the nucleation of 90 degrees 1/6[112] partial dislocations from a tensile interface is much shallower than that of 60 degrees 1/2[110] perfect dislocations from a compressive interface. A critical thickness model for the interface nucleation of these dislocations is developed as a modification of the classical surface nucleation model.