Gold-tantalum alloy films deposited by high-density-plasma magnetron sputtering

Gold-tantalum alloy films are of interest for biomedical and magnetically-assisted inertial confinement fusion applications. Here, we systematically study the effects of substrate tilt (0 degrees-80 degrees) and negative substrate bias (0-100 V) on properties of less than or similar to 3-mu m-thick films deposited by high-power impulse magnetron sputtering (HiPIMS) from a Au-Ta alloy target (with 80 at. % of Ta). Results reveal that, for all the substrate bias values studied, an increase in substrate tilt leads to a monotonic decrease in film thickness, density, residual compressive stress, and electrical conductivity. Larger substrate bias favors the formation of a body-centered cubic phase, with films exhibiting lower column tilt and higher density, electrical conductivity, and residual compressive stress. These changes are attributed to metal atom ionization effects, based on the lack of correlation with distributions of landing energies and incident angles of depositing species as calculated by Monte Carlo simulations of ballistic collisions and gas phase atomic transport. By varying substrate tilt and bias in HiPIMS deposition, properties of Au-Ta alloy films can be controlled in a very wide range, including residual stress from -2 to +0.5 GPa, density from 12 to 17 g/cm(3), and the electrical resistivity from 50 to 4500 mu Omega cm, enabling optimum deposition conditions to be selected for specific applications.

Automated summary

Gold-tantalum alloy films deposited by high-power impulse magnetron sputtering show properties affected by substrate tilt and bias, with increased tilt leading to decreased film thickness, density, compressive stress, and electrical conductivity. Substrate bias influences the formation of body-centered cubic phase, affecting film properties such as density, electrical conductivity, and residual stress. The changes observed are attributed to metal atom ionization effects rather than distributions of energies and angles, enabling control over properties for specific applications.