Deposition rate and substrate temperature effects on the structure and properties of bulk-sputtered OFHC Cu and Cu–O.15 Zr

Abstract

Deposition rate and substrate temperature were observed to affect the structure and properties of thick, sputtered OFHC copper and Cu–0.15 Zr deposits. Deposition of OFHC Cu and Cu–0.15 Zr was performed by high-rate sputtering from a cylindrical (hollow) cathode. Bulk deposits varying from 250 to 3700 μ thichnesses were evaluated as to microstructure, surface topography, and fractography. At conditions of low substrate temperature, crystallite size and openness of the structure increased with increasing deposition rate for both materials. At elevated temperatures it was possible to produce an equiaxed, ductile structure of OFHC Cu, but only at low deposition rates. At higher deposition rates open structures resulted having recrystallized, equiaxed grains within large, poorly bonded crystallites. Sputtered Cu–0.15 Zr deposited at basically equivalent conditions, as used for OFHC Cu, exhibited open-type structures for all conditions evaluated. However, lower deposition rates significantly reduced the openness of the structure, as did increasing substrate temperature. The use of a triode discharge to achieve a higher degree of ion bombardment in biasing was effective in generating a dense, non-voided structure of Cu–0.15 Zr.