The effect of annealing heavily C-doped film samples was studied by using double-crystal X-ray diffractometric and transmission electron microscopic techniques. The evolution of compressive strains in C-doped films was observed, by means of X-ray diffractometry, during isochronal annealing. Cross-sectional transmission electron microscopy revealed the presence of unusual misfit dislocations, with extra half-planes, on the GaAs side of annealed (900C, 0.5h) samples. These were in addition to normal misfit dislocations, with extra half-planes, on the film side. A possible mechanism for the formation of such misfit dislocations was based upon the over-relaxation of misfit strains in the film.

H.Sohn, E.R.Weber, S.Nozaki, K.Takahashi: Applied Physics Letters, 1995, 67[8], 1104-6