Interfacet surface diffusion in selective area epitaxy of III–V semiconductors

In this letter, we discuss the interfacet diffusion of group-III species from {111} B facets to the (100) plane in planar selective area epitaxy. In general, this leads to enhanced vertical growth at the edges of the (100) surface. From such edge profiles, several groups have extracted adatom “diffusion lengths” of ∼1 μm. This is a factor of 100 larger than reported diffusion lengths obtained by reflective high energy electron diffraction, scanning tunneling microscopy, or growth-rate analysis. We show that these values are severely overestimated and that edge profiles only give information on the propagation velocity of macrosteps.