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 was carried out under the following conditions: Nz gas pressure 6.7 x 10(-2) Pa RF pou er 400W and the evaporation rate of SiN 0.2nm/sec. Substrate temperature was changed from 290 degrees C (unheated, only radiation) to 750 degrees C. The thickness of the SiN films as the first layer was 90nm. Furthermore, Titanium (Ti thin film as the first layer was prepared by vacuum deposition. The thickness of the Ti film was 70nm. 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 temperature, with accelerating voltage of 70kV. After that SiN films were deposited up to the total thickness of 500nm by the same method as stated above. X-ray diffraction showed that the structure of the films was amorphous. X-ray photoelectron spectroscopy revealed the muring la);er at the interface between the substrate and SiN films. The adhesion strength was estimated by a scratch rest. It was found that Ti ion implantation enhanced the adhesion strength between the SiN film and the substrate. The corrosion resistance of the specimens was evaluated in aqueous solutions of sulfuric acid (5% H2SO4, 30 degrees C) by an electrochemical method. The formation of an interfacial mixing layer by Ti ion implantation was extremely effective for improving the protectiveness of films.