Thin-film interdiffusion. II. Ti-Rh, Ti-Pt, Ti-Rh-Au, and Ti-Au-Rh

Abstract
Interdiffusion in the Ti/Rh/Au and Ti/Pt thin‐film systems is measured using Rutherford backscattering. Extensive grain size measurements are used to interpret the data in terms of grain‐boundary‐assisted bulk diffusion. At room temperature, rapid grain‐boundary diffusion of Au into the fine‐grained Rh layer of the Ti‐Rh‐Au films occurs, characterized by a diffusion coefficient DB∼10−16 cm2/sec. The bulk diffusion of Au into the grains of the Rh film layer is examined using the grain‐boundary‐assisted bulk diffusion model, and the influence of surface segregation and size effects is discussed. It is found that interdiffusion in Ti‐Rh and Ti‐Pt couples is much slower than in Ti‐Pd or Ti‐Au. Methods are suggested by which the utility of Ti‐Rh‐Au as a conductor metallization might be improved.