Deposition of nanocomposite thin films by a hybrid cathodic arc and chemical vapour technique
Faculty of Computing, Health and Science
School of Engineering
A hybrid technique is described for the synthesis of nanocomposite Ti–Si–N thin films based on the reactive deposition of Ti produced from a cathodic arc source and silicon from a liquid tetramethylsilane (TMS), precursor. The influence of the TMS flow rate on the structure and mechanical properties has been investigated. The film structure was found to comprise TiN crystallites and amorphous Si3N4. The X-ray diffraction data showed that with increasing TMS flow there is a decrease in the TiN crystalline size from 33 nm to 4 nm. The hardness of the films was found to be strongly dependent on the Si content and reached a maximum value of 41 GPa at ∼ 5% Si content at a total pressure of nitrogen and TMS of 0.8 Pa. Hardness enhancement was found to arise from the nanostructural change induced due to the addition of an amorphous Si3N4 phase into the film. Transmission electron microscopy (TEM) analysis confirmed the structure of the Ti–Si–N composites.