Effect of oxygen concentration and system geometry on the current–voltage relations during reactive sputter deposition of titanium dioxide thin films

Current–voltage relations at different magnetron sputtering systems and gas mixtures were studied during reactive sputter deposition of titanium dioxide thin films. The main goal of this work was to investigate the influence of reactive gas mixture (Ar + O2) and system geometry on the electrical characteristics of the discharge. The geometries utilized were the conventional magnetron sputtering, hollow cathode magnetron sputtering and triode magnetron sputtering. A change in the system geometry leads to a change in the electric field distribution, which alters the working range of the discharge voltage and magnetron efficiency. It is noticed that the discharge voltage at constant current can be reduced when the geometry is altered from conventional magnetron to hollow cathode magnetron or triode magnetron, at the same time the magnetron efficiency is increased when hollow cathode magnetron or triode magnetron are used instead of conventional magnetron sputtering.

► Alteration on electrode configuration leads to an increase in magnetron efficiency.
► Increased oxygen concentration increases the working voltage and the magnetron efficiency.
► TMS system operates in lower voltages compared to MS and HCMS systems.