Lawrence Berkeley National Laboratory

Experiments have shown that the presence of a thin native oxide layer on the surface of a strained SiGe epilayer causes an order of magnitude increase in dislocation velocities during annealing over those observed in atomically clean samples and during crystal growth. This behavior is explained herein by stress-assisted dislocation kink nucleation at the oxide/epilayer interface. Finite element models are used to estimate the magnitude of stress local to steps at this interface due to both intrinsic and thermal expansion stresses, and dislocation theory is used to determine the resulting increase in single kink nucleation.