Misfit dislocation interactions in low mismatch p/p(+) Si

We studied the propagation and interaction of individual misfit dislocation s in strained p/p(+) Si wafers. Relaxation of misfit strain occurs at the w afer edge during high-temperature epitaxial growth. The thick epitaxial lay er (about five times the critical thickness) and low misfit dislocation den sities (similar to 100 cm(-1)) are highly compatible with a non-destructive study via x-ray topography. We determined that as a gliding 60 degrees mis fit dislocation encounters a strain field in its path, it cross-slips to a specific lattice direction. Misfit dislocation segments with either an orth ogonal or quasi-parallel tin the case of the off-oriented substrate) glide direction of the Burger's vector were determined to act as cross-slip initi ation sites. This interaction happens during layer growth as well as post-g rowth annealing cycles. We did not find a case of misfit dislocation blocki ng during sample annealing, No occurrence of annihilation or multiplication reaction of crossing dislocations was detected during our studies. We show that, due to geometry, a distribution of lilt across the wafer surface res ults from preferential cross-slipping events. Our results are applicable to early stages of strain relaxation in other strained systems, like graded b uffer layers.