Annealing effect on the optical properties of gold films deposited on silicon substrates

The refractive indices of gold films deposited on (111) silicon wafers are measured by a polychromatic ellipsometer at various annealing temperatures below 300 degrees C. The reflectivity increases slightly during the initial 260 degrees C annealing stage and then decreases drastically by 40% near 2.06 eV as the annealing temperature rises to 293.5 degrees C. Etch pits are found on the surface as the temperature rises further.