Reactively Sputtered W‐N Films as Diffusion Barriers in GaAs Metallizations

Abstract

The stability of reactively sputtered tungsten‐nitrogen alloy thin films is investigated for application as diffusion barriers between and Au, Ag, or Al metal layers. The composition of W‐N barriers is varied over a wide range, including pure W. We find that W‐N layers prevent the interdiffusion and reaction between Au or Ag metal overlayers and up to at least 550° and 600°C heat‐treatments, respectively, for 30 min annealing in forming gas. Metallurgical interactions in the and systems have been studied by backscattering spectrometry, sheet resistance measurements, SEM, and EDAX analysis.