<title>Reactive sputtering of highly insulating layers with twin-cathode and mid-frequency power supply</title>

Abstract

The arcing problem in reactive sputter processes for deposition of highly insulating materials and its possible sources are discussed. It is argued that most of the arcs are initiated by electrical breakdown processes of the insulating layer on the magnetron cathode. The methods to avoid arcs are considered. The theoretical studies lead to a new set up, using a mid- frequency ac power supply and a twin-cathode arrangement. With this set up the charging up of the insulating layer, which leads to the process instabilities, is reduced to an acceptable limit. Using this arrangement transparent layers of SiO2 were produced without arcing over the entire lifetime of the target (more than one week). The deposition rate obtained for these films was 8 nm/sec which is nearly 10 times higher than for the conventional magnetron sputter arrangement. The refractive index of the transparent layers was controlled by oxygen amount in the sputter chamber. Values obtained for n range from 1.45 to 1.6. Results of chemical and mechanical durability tests have shown that the prepared layers are suitable for industrial application.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.