High-resolution electron microscopy was used to characterize the microstructure of thin films which had been grown by plasma-enhanced molecular beam epitaxy. Zincblende and wurtzite polytypes were preferentially nucleated by using (001) GaAs and (00•1) 6H SiC substrates, respectively. It was found that stacking faults and micro-twins along {111} planes predominated in the zincblende films, while stacking faults along {00•2} planes (and threading defects that originated at the substrate surface) were most prevalent in the wurtzite phase. An improved crystal quality was obtained by growing the films on suitable buffer layers.

D.Chandrasekhar, D.J.Smith, S.Strite, M.E.Lin, H.Morkoç: Journal of Crystal Growth, 1995, 152[3], 135-42