Ni-Au layers on sapphire prepared by direct current magnetron sputtering

Thin bimetallic Ni-Au layers (similar to 100 nm) with three different Au content were prepared by direct current magnetron sputtering onto sapphire substrates. The elemental composition and the layer thickness of bimetallic layers were controlled during the sputtering process. The prepared Ni-Au layers were annealed at temperatures of 400 degrees C and 900 degrees C in the air to determine the behavior of Au and Ni in the layers after heating. The elemental composition and depth profiling was provided by Rutherford backscattering spectrometry (RBS). The surface morphology was examined via Scanning electron microscopy (SEM). RBS measurement revealed inter-diffusion Au into sapphire substrate after thermal annealing and the formation of grains and voids.