The dislocation plasticity of a thin Cu film on a SiNx/SiOx-coated Si wafer was monitored by means of transmission electron microscopy during the thermal cycling of a cross-sectional specimen. The in situ transmission electron microscopic study revealed jerky dislocation motion at low homologous temperatures, while continuous dislocation glide occurred at high temperatures. Moreover, dislocations were pulled into the Cu/SiNx interface; where dislocation contrast disappeared. It was concluded that the limited mobility of dislocations at low homologous temperatures, rather than interfacial dislocation segments, was responsible for the high yield stress of the Cu film.

in situ Transmission Electron Microscopy Study of Dislocations in a Polycrystalline Cu Thin Film Constrained by a Substrate. G.Dehm, E.Arzt: Applied Physics Letters, 2000, 77[8], 1126-8