Electron Microscopy Studies of the Alloying Behavior of Au on GaAs

Single crystal GaAs samples, containing Au films of thicknesses in the range 400 to 4500 Å, have been alloyed at 550 °C for variable periods of time. Transmission electron microscopy studies of the substrate have revealed the presence of hexagonal AuGa, Au precipitation, and high dislocation densities as a function of depth into the sample. A thin heavily disordered near-surface region has been shown to arise from the high Au concentration and the outdiffusion of Ga and As at longer processing times.