In this paper, an atmospheric pressure plasma jet driven by an AC power supply was applied for SiOx film deposition on a metal surface. To improve the adhesion strength between the film and substrate, the processes of plasma etching and annealing were applied. The deposited SiOx film properties, including film thickness, surface morphology, chemical composition and electrical properties, were studied systematically. In addition, the deposited film was used for the metal particle lift-off voltage in a gas-insulated line (GIL) system. Our results showed that the adhesion strength between the film and substrate was 5 times higher in the films subjected to plasma etching and annealing treatment than that in the untreated group. The high oxygen content attained in the SiOx film after the etching and annealing processes was responsible for the adhesion force improvement. The composition changes in the film also increased the relative constant value, which was in good agreement with the metal particle lift-off voltage results. After thermal annealing, the sample showed a 119% improvement in the lift-off voltage compared to that of the bare electrode.