Strained layer heterostructures provide ideal systems with which to
study the dynamics of dislocation motion via in situ transmission electron
microscopy, as the geometry, strain state, and kinetics can be
characterized and directly controlled. We discuss how these structures are
used to study dislocation-point defect interactions, emphasizing the
experimental requirements necessary for quantification of dislocation
motion. Following ion implantation, different concentrations and types of
point defects are introduced within the SiGe epilayer depending on the
implantation species, energy, and current density. By annealing samples in
situ in the transmission electron microscope (TEM) following implantation,
we can directly observe dislocation motion and quantify the effect of
dislocation-point defect interactions on dislocation velocities. We find
that dislocation motion is impeded if the implantation dose peak lies
within the epilayer, as dislocations pin at point defect atmospheres.
Shallow BF2 implantation into the sample capping layer results
in more complicated behavior. For low current density implants,
dislocation velocities may be dramatically increased; at higher current
densities the magnitude of this increase is significantly smaller.
Implantation of different ions separately implicates fluorine as the
species responsible for the observed increases in dislocation velocities,
presumably due to an electrical effect on the rate of dislocation kink
nucleation.