TITANIUM NITRIDE DEPOSITED BY PLASMA-ASSISTED CHEMICAL VAPOR-DEPOSITION

A new type of plasma reactor for plasma-assisted chemical vapour deposition of titanium nitride (TiN) has been designed and built. The reactor uses an r.f. discharge operating at a pressure around 1 mbar and at a frequency of 13.56 MHz. The substrates were placed on the r.f. electrode. The colour, Vickers hardness, thickness, chemical composition (by Auger electron spectroscopy), structure (by X-ray diffraction) and morphology (by scanning electron microscopy) of the deposited films were determined. The experiments show that the uniformity of the deposited layer on the samples situated on different places on the substrate holder depends on the design of the gas inlet and gas distribution. The uniformity of the deposition on three-dimensional substrates depends also on the substrate bias. At relatively high bias voltages the layer on the edges has a different composition to that on plane surfaces, whereas at lower bias voltages uniform composition can be achieved. It could be demonstrated that TiN coatings of excellent quality can be deposited on all surfaces of objects of complex geometry at low temperatures (450-550 °C). The quality of these coatings is equivalent to the quality obtained by conventional chemical vapour deposition and physical vapour deposition techniques. © 1990.