Reactive sputtered TixNbyNz thin films. I : basic processing relationships

Ti x Nb 1-x N coatings have been deposited onto silicon substrates using reactive DC co-sputtering of titanium and niobium targets. The coatings range in composition from TiN to NbN with mixtures taking the general form of Ti x Nb 1-x N. Using standard materials characterisation techniques (SEM, AFM, EDS, GA-XRD), the films have been assessed for their deposition rate, grain size, surface roughness, composition and structure as a function of applied Ti/Nb discharge power. This preliminary investigation has shown that the basic characteristics of these coatings tend to display a consistent trend with the applied discharge power. This provides a convenient method for deposition control. It has also been identified that the respective sensitivity to nitrogen poisoning by the Ti and Nb targets is an important point of consideration during processing. Further investigations are needed to gain a more complete understanding of how Ti x Nb 1-x N coatings may be deposited to achieve optimized performance under orthopaedic applications. The present investigation is considered the first dedicated attempt to acquire such control