Deposition of TiN films using a thermal plasma reactive forming technology

TiN films have been deposited on graphite substrates by a novel reactive plasma technique. In this process, NH3 and TiCl4 are reacted in the jet of a plasma torch and are deposited onto a substrate forming TIN films at a high growth rate (above 2 mu m min(-1)). It was found that the process parameters strongly affect the microstructure, thickness, density, and growth rate of the TiN films. These parameters include N:Ti ratio, temperature of substrate, spray distance and radial position away from the impingement point. In general, it was found that thick and dense coatings were deposited when the N:Ti ratio was kept low and the substrate temperature was high. Very dense and thin TiN coatings were deposited 3-4 cm away from the impingement point. These coatings are believed to be the result of a gas phase (chemical vapour deposition type) reaction. The limitations and advantages of this technique are also discussed in this paper.