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

In this letter, we discuss the interfacet diffusion of group-III species fr om {111} B facets to the (100) plane in planar selective area epitaxy. In g eneral, this leads to enhanced vertical growth at the edges of the (100) su rface. From such edge profiles, several groups have extracted adatom "diffu sion lengths" of similar to 1 mu m. This is a factor of 100 larger than rep orted diffusion lengths obtained by reflective high energy electron diffrac tion, scanning tunneling microscopy, or growth-rate analysis. We show that these values are severely overestimated and that edge profiles only give in formation on the propagation velocity of macrosteps. (C) 1999 American Inst itute of Physics. [S0003-6951(99)04115-7].