Dense Al2O3 films prepared by high power impulse magnetron sputtering at pulsed kV bias

Al2O3 films are often used in electronic and other devices for surface protection due to their excellent insulating and mechanical properties, but these properties depend on the film density. Conventional magnetron sputtering used industrially to deposit Al2O3 films faces challenges in density regulation, and many Al2O3 coatings have poor densities. Herein, negative kV biases are applied to the substrate in high-power impulse magnetron sputtering (HiPIMS) to produce the desirable high-energy ions to densify the Al2O3 films. Our results indicate that the high pulsed bias also mitigates arcing during the deposition of insulating alumina films. By increasing the pulsed voltage, the film density increases, resulting in higher optical transparency, better insulating and mechanical properties, as well as superior corrosion resistance.