Kinetic critical thickness for surface wave instability vs. misfit dislocation formation in GexSi1−x/Si (100) heterostructures

The kinetic critical thicknesses for surface wave formation and misfit dislocation generation in UHVCVD-grown GeSi/Si have been quantitatively determined using microscopical techniques. A refined morphological instability theory has been developed using a coupled continuum/atomistic treatment that incorporates a nucleation barrier to the onset of surface wave formation. The theory accurately predicts the onset of surface wave formation as a function of thickness, composition, temperature and deposition rate. The interplay between misfit dislocation generation and surface wave formation can be elucidated from two-dimensional strain relaxation instability diagrams obtained from a 4-D parameter space.