X-ray diffraction studies of evaporated gold thin films deposited on aluminum nitride substrates

Abstract

X-ray diffraction was utilized to determine the root mean square (r. m.s.) strains and average particle sizes in evaporated gold thin films on aluminum nitride substrates as a function of substrate surface condition prior to deposition. The substrate treatments evaluated were surface roughness, use of titanium and chromium inter-layers, presence of an oxide layer on the substrate surface and vacuum conditions used during deposition. The Warren-Averbach method was utilized to obtain the r.m.s. strains and particle sizes form peak breadth data, using both cosine and modulus methods. It was concluded that the highest strain deviations and, therefore, the largest film plastic deformation occurred when the substrate surface was rough, when chromium was used as an inter-layer and when ultra high vacuum conditions were used during deposition. It is proposed that for a fixed film-substrate system, the r.m.s. strain, which is indicative of the level of plastic deformation in the film induced due to differential contraction following deposition, may serve as an indirect measure of the interfacial adhesion