B. Pichaud et al., Elemental dislocation mechanisms involved in the relaxation of heteroepitaxial semiconducting systems, PHYS ST S-A, 171(1), 1999, pp. 251-265
Different elemental dislocation mechanisms are considered and we try to hig
hlight their special behaviour in relation to the layer geometry. The nucle
ation of misfit dislocations is the first step, we show here that the mecha
nism proposed by Matthews et al. can actually be observed in low misfit sys
tems. The development of dislocations is then studied and we underline some
particular problems which could influence the dislocation length: the role
of the cooling step and of the uncertainty on G(dk), the formation energy
of kink pairs. The interactions between emerging segments or an emerging se
gment and a misfit dislocation are reviewed. Finally the role of dislocatio
n cross slipping is discussed and it is shown that in epitaxial stressed fi
lms this mechanism is favoured by the shrinkage of the fault ribbon.