A controlled pulsed reactive magnetron sputtering process for oxide film deposition

Thin oxide films deposited by reactive magnetron sputtering have found a widespread application in low cost mass-production. Using pulsed discharges and controlling the deposition in the instable transition mode by a fast closed loop circuit and piezoelectric valves for the reactive gas supply gives access to high deposition rates and advanced functional film properties. We have used a dual magnetron source powered by a sine wave MF generator. In comparison to common twin magnetrons, our dual magnetron consists of two single magnetrons. The targets were spatially separated with distance of 210 mm. Both sources were equipped with individual hidden anodes and plasma shielding. To avoid instabilities of the target state in the deposition process, we merged the reactive gas supply for both sources. We have used this magnetron in the transition mode to deposit MgO from an Mg target and indium tin oxide (ITO) using an In:Sn target. The optical extinction coefficient was about 10-4 for the MgO films and approximately 10-2 for the ITO films, being acceptable for many low cost applications. The electrical resistivity of dynamically deposited ITO films is around 10-3 µcm. At a power density of 3.85 Wcm2 in both cases a very high deposition rate could be achieved.