Enhancement of dislocation velocities by stress-assisted kink nucleation at the native oxide/SiGe interface

Experiments have shown that a native oxide layer on the surface of a strain ed SiGe epilayer causes an order of magnitude increase in dislocation veloc ities during annealing over those observed in atomically clean samples and during crystal growth [E. A. Stach, R. Hull, R. M. Tromp, M. C. Reuter, M. Copel, F. K. LeGoues, and J. C. Bean, J. Appl. Phys. 83, 1931 (1998)]. This behavior is explained herein by stress-assisted dislocation kink nucleatio n at the oxide/epilayer interface. Finite element models are used to estima te the stress local to steps at this interface due to both intrinsic and th ermal expansion stresses, and dislocation theory is used to determine the r esulting increase in single kink nucleation. (C) 2001 American Institute of Physics.