Wetting and energetics of solid Au andAu–Ge/SiC interfaces

Abstract A solid state wetting technique has been used to investigate the effects of alloying Au with Ge on the wetting and energetics of Au/SiC interfaces at 1123 K. Germanium was found to segregate to the Au/SiC interface, thereby lowering the contact angle of Au on SiC from 133 to 110°, and doubling the work of adhesion of Au on SiC. Calculations based on a monolayer model predict a segregation of 0.89 monolayers of Ge at the Au/SiC interface for Au containing 2.3 at.% Ge. This agrees reasonably well with a coverage of 0.6 monolayers Ge at the Au/SiC interface obtained by direct measurements based on the crater edge profiling technique. The work also demonstrates that simple models of interfacial composition can be combined with the Gibbs adsorption isotherm to provide reliable estimates of interfacial composition at complex four-component interfaces.