The velocities of misfit dislocation threading segments were measured in real time, using ultra-high vacuum transmission electron microscopy, during the ultra-high vacuum chemical vapor deposition of thin SiGe epilayers on Si(001). No measurable difference in dislocation velocity was observed during growth and during the post-growth annealing of samples with an atomically clean surface. This contrasted with previous observations of the InGaAs/GaAs (001) system. However, dislocations were seen to move some 3 times slower during growth and during post-growth ultra-high vacuum annealing than during the annealing of samples which had a native oxide at the surface. Post-growth deposition of As and O was used to investigate the effect of the surface condition upon the dislocation velocities, and possible causes of the increase in dislocation velocity in the presence of a native oxide. The results suggested that a previously unknown interaction occurred between moving dislocations and free surfaces in this system.

E.A.Stach, R.Hull, R.M.Tromp, M.C.Reuter, M.Copel, F.K.LeGoues, J.C.Bean: Journal of Applied Physics, 1998, 83[4], 1931-7