Sputter deposition of high electrical resistivity Au-Ta alloy coatings on rotating substrates

Sputter deposition of gold-tantalum alloy coatings is a key process for manufacturing hohlraums for magnetically-assisted inertial confinement fusion implosions. Here, we describe direct current magnetron sputter deposition of similar to 10 - mu similar to 10 - mu m-thick films of Au-80 at.% Ta onto rotating sphem-cylindrical hohlraum and planar Si witness substrates. Emphasis is given to how film microstructure and properties are affected by main deposition parameters, including argon working gas pressure, substrate bias, and the source composition (a single alloyed target compared to co-sputtering from two elemental targets). Experimental findings are correlated with distributions of landing energies and incident angles of depositing species calculated by Monte Carlo simulations of ballistic collisions and gas phase atomic transport. Deposition conditions characterized by low energetics of depositing species favor the formation of a beta-Ta-like phase. Implications of these results to hohlraum fabrication are discussed.

Automated summary

This article describes the process of manufacturing gold-tantalum alloy coatings using direct current magnetron sputter deposition, and discusses in detail the impact of deposition parameters on film microstructure and properties. Experimental findings are correlated with simulation results, and it is found that low-energy depositing species favor the formation of a specific phase.