Low-temperature deposition of titanium nitride

A new technique for depositing hard, dense, well-adhering TiN with excellent adhesion is described. Taking advantage of the high degree of ionization of the material emitted from a cathodic are source, a short, very high voltage pulse (the order of 5-20 kV for 1-3 mu s at a frequency of some 1-2 kHz) is applied to the substrate in addition to the usual d.c. bias during reactive deposition. The high bias accelerates the ions located within the sheath during the short pulse and their momentum modifies the properties of the coatings as indicated above. The technology, termed Hyper-Ion, is readily retrofitted to existing physical vapor deposition systems equipped with cathodic are sources. The present work presents results on titanium nitride deposited onto temperature-sensitive materials including low alloy steel, and aluminum 6061-T6 at a substrate temperature of 150 degrees C. The coating has a type-T microstructure and the substrates do not lose mechanical strength.