Surface morphology of related Ge<i>x</i>Si1−<i>x</i> films

Abstract

We have investigated the surface morphology of relaxed, compositionally graded GexSi1−x structures, to illustrate the influence of defect-related strain fields on film growth. Quantitative topographic measurements via scanning force microscopy show that the roughness associated with the cross-hatch patterns, due to underlying misfit dislocations beneath the surface, increases as the final Ge concentration or the grading rate increases. We further show that strain fields arising from the termination of threading dislocations at the surface result in shallow depressions.