FORMATION OF SILICON-NITRIDE THIN-FILMS BY RF ION PLATING AND THEIR PROPERTIES

Silicon nitride (SiN) thin films were prepared on austenitic type 316L stainless steel substrates by RF ion plating method. Film formation w as carried out under the following conditions: Nz gas pressure 6.7 x 1 0(-2) Pa RF pou er 400W and the evaporation rate of SiN 0.2nm/sec. Sub strate temperature was changed from 290 degrees C (unheated, only radi ation) to 750 degrees C. The thickness of the SiN films as the first l ayer was 90nm. Furthermore, Titanium (Ti thin film as the first layer was prepared by vacuum deposition. The thickness of the Ti film was 70 nm. These specimens were irradiated with titanium ions at a fluence of 1 x 10(17) ions/cm(2), by use of metallic ions source with room tempe rature, with accelerating voltage of 70kV. After that SiN films were d eposited up to the total thickness of 500nm by the same method as stat ed above. X-ray diffraction showed that the structure of the films was amorphous. X-ray photoelectron spectroscopy revealed the muring la);e r at the interface between the substrate and SiN films. The adhesion s trength was estimated by a scratch rest. It was found that Ti ion impl antation enhanced the adhesion strength between the SiN film and the s ubstrate. The corrosion resistance of the specimens was evaluated in a queous solutions of sulfuric acid (5% H2SO4, 30 degrees C) by an elect rochemical method. The formation of an interfacial mixing layer by Ti ion implantation was extremely effective for improving the protectiven ess of films.