R.F. reactively sputtered TiN: Characterization and adhesion to materials of technical interest

Films of TiN were prepared by reactive r.f. sputtering of titanium in an ArN 2 atmosphere. Materials of great technological importance, such as high speed steel, stainless steel and a nickel alloy were coated. Characteristic properties of the deposits such as the deposition rate, the microhardness, the electrical resistivity and the adhesion to the substrate were investigated in relation to the partial pressures of N 2 and argon during deposition. The composition of the deposit which was found to give the maximum hardness was determined by microprobe analysis. It was shown to be nearly stoichiometric. The suitable N 2 partial pressure range which gives golden yellow films of stoichiometric composition was shown to depend mainly on the applied r.f. power and argon partial pressure. The adhesion of the coatings to different substrates was investigated by the scratch test. On high speed steel it was found that the critical load at which the coating is stripped becomes constant for coating thicknesses above about 4 μm.