Improvement in heteroepitaxial film quality by a novel substrate patterning geometry

Abstract

We describe a novel substrate patterning geometry which can reduce epilayer threading dislocation densities by up to two orders of magnitude in GexSi1−x/Si(100) (x∼0.15–0.20) het- eroepitaxial layers. The basic pattern consists of a two-dimensional array of ∼2 μm diameter oxide pillars which are separated from each other by varying pitch dimensions, and which are staggered slightly from their neighbors with respect to the in-plane 〈011〉 directions. This ensures that a misfit dislocation nucleating at any point within the epilayer must eventually propagate into one of the pillars, where the threading end will be terminated. Prospects for surface planarization and overgrowth of the pillars are discussed.