Au diffusion in amorphous and polycrystalline Ni/sub 0.55/ Nb/sub 0.45/

Diffusion of Au in amorphous and polycrystalline Ni/sub 0.55/ Nb/sub 0.45/ has been studied by Rutherford backscattering spectroscopy of heat-treated Au/NiNb couples. The diffusion process is characterized by interdiffusion of Nb and Au with NiNb showing a Au miscibility of approx.20 at. %. The Au diffusion coefficient in polycrystalline NiNb at 400 0C was found to be 1.6 x 10-15 cm2/s. The diffusion coefficient for Au in amorphous NiNb was found to be substantially less, approx.10-21 cm2/s at 400 0C. These results support the concept of using amorphous films as metallizations or diffusion barriers in high-temperature solid-state device applications