INTERFACIAL REACTIONS IN AG-ZN THIN-FILM COUPLES

Interfacial reactions in AgZn thin film couples have been investigated by measuring the contact resistance and composite electrical resistance with time and temperature in order to understand the kinetic behaviour of the system. The resistivity measurements have been supplemented by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The activation energy of diffusion has been found to be 6.1 × 10-20 J from electrical resistivity measurements where the model assumes rapid grain boundary diffusion followed by a defect-assisted path for diffusion into the grain and 8.3 × 10-20 J from contact resistance measurements where the model is based on grain boundary diffusion. XRD indicates the growth of ß′-AgZn phase even at room temperature which changes to the ß phase above 250°C. SEM confirms the diffusion of silver through zinc grain boundaries, especially at the interface boundary. TEM indicates the growth of grain size with annealing and confirms the presence of the ß′ phase. © 1990.