The propagation and interaction of individual misfit dislocations in strained p/p+ wafers were studied. The relaxation of misfit strain occurred at the wafer edge during high-temperature epitaxial growth. Thick epitaxial layers (some 5 times the critical thickness) and low misfit-dislocation densities (about 100/cm) were suitable for non-destructive study via X-ray topography. It was determined that, when a gliding 60° misfit dislocation encountered a strain field in its path, it cross-slipped in a specific lattice direction. Misfit dislocation segments with either an orthogonal or quasi-parallel (in the case of off-oriented substrates) glide direction of the Burgers vector were suggested to act as cross-slip initiation sites. This interaction occurred during layer growth, as well as post-growth annealing cycles. No cases of misfit dislocation blocking were found during sample annealing. No annihilation or multiplication-reaction of crossing dislocations was detected. It was shown that, due to the geometry, a distribution of the tilt across the wafer surface resulted from preferential cross-slipping events. The results were applicable to the early stages of strain relaxation in other strained systems, such as graded buffer layers.

Misfit Dislocation Interactions in Low Mismatch p/p+ Si. P.Feichtinger, B.Poust, M.S.Goorsky, D.Oster, J.Chambers, J.Moreland: Journal of Physics D, 2001, 34[SA], 128-32