We have studied deformation mechanisms at epitaxial semiconductor interfaces, primarily in the GexSi1-x/Si and InxGa1-xAs/GaAs systems, by in-situ annealing of metastably strained films in the transmission electron microscope (TEM). This allows direct, real-time, observation and recording of dynamic strain relaxation phenomena such as misfit dislocation nucleation, propagation and interaction mechanisms. This geometry also allows considerable insight into fundamental dislocation physics, as we are able, for example, to accurately quantify dislocation propagation velocities as functions of well-defined effective stresses (in the 108 - 109 pa regime)in the epitaxial layers, and to vary dislocation structure and character by varying the orientation of the epitaxial interface. Comparison with measurements of dislocation velocities in bulk semiconductors and with models of dislocation motion via kink propagation, allows extension of existing measurements and models to the thin film, high stress regime.
Precise measurement of activation parameters for individual dislocation nucleation during in situ TEM tensile testing of single crystal nickel
