Au diffusion in amorphous and polycrystalline Ni0.55 Nb0.45

Abstract

Diffusion of Au in amorphous and polycrystalline Ni_0.55 Nb_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 ∼20 at. %. The Au diffusion coefficient in polycrystalline NiNb at 400 °C was found to be 1.6×10⁻¹⁵ cm²/s. The diffusion coefficient for Au in amorphous NiNb was found to be substantially less, ∼10⁻²¹ cm²/s at 400 °C. These results support the concept of using amorphous films as metallizations or diffusion barriers in high‐temperature solid‐state device applications.