Dual-anode magnetron sputtering

Reactive sputtering of dielectrics suffers from an anode problem, which appears when the anode becomes coated with a dielectric layer. A solution to the anode problem is a self-cleaning anode system. It can consist of two anodes and a single magnetron driven by a mid-frequency AC power supply via a center-taped transformer. The anodes are connected to the ends of the secondary coil of the transformer, while the magnetron to its center tap. Such a novel configuration is called dual-anode sputtering system, and has been developed in this work. This configuration creates a self-cleaning regime for both anodes, and provides dynamically cleaned and sustainable anodes. To provide biasing, the substrate holder is connected to the magnetron through a resistor and/or additional floating power supply. Introducing dual anodes does not restrict application of closed-loop control for high rate deposition of transparent and scratch-resistant Al2O3 films. High-rate deposition of dielectrics, using biased dual-anode reactive sputtering, has been proved to be a reliable technology for making dense Al2O3 and other films.