Effect of titanium adhesion layer on iridium thin film optical properties

The refractory metal iridium is useful for highly reflective mirrors for x-ray astronomy and high temperature plasmonic applications like selective emitters. However, the deposition conditions of the thin film can produce very different optical properties which will affect the final performance of the optical device. In this study, we report on the optical properties, crystal structures, and surface roughness of Ir thin films produced by dc magnetron sputtering. The chamber pressure was varied from 10 mTorr to 25 mTorr with a constant plasma power of 160 W. Films deposited on a titanium adhesion layer or directly on a silicon substrate will be compared.