ZIN-SITU STUDIES OF THE INTERACTION OF DISLOCATIONS WITH POINT-DEFECTS DURING ANNEALING OF ION-IMPLANTED SI SIGE/SI(001) HETEROSTRUCTURES/

Strained layer heterostructures provide ideal systems with which to st udy the dynamics of dislocation motion via in situ transmission electr on microscopy, as the geometry, strain state, and kinetics can be char acterized 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 sa mples 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 vel ocities. We find that dislocation motion is impeded if the implantatio n dose peak lies within the epilayer, as dislocations pin at point def ect atmospheres. Shallow BF, implantation into the sample capping laye r results in more complicated behavior. For low current density implan ts, dislocation velocities may be dramatically increased; at higher cu rrent densities the magnitude of this increase is significantly smalle r. Implantation of different ions separately implicates fluorine as th e species responsible for the observed increases in dislocation veloci ties, presumably due to an electrical effect on the rate of dislocatio n kink nucleation.