Study On Properties Of TiN And ZrN Films Deposited By Magnetron Sputtering

Resulting from the exhibition of both metallic and covalent bonding characteristics, the TiN and ZrN films have interesting properties such as high melting points, high hardness, excellent thermal and chemical inert, good conductivity and metallic reflectivity. Therefor, those films can be used as hard-coating thin films to expand lifetimes of mechanical compound such as cutting tools and dies. For decorative purpers, TiN and ZrN are also employed in some case. In electronic industry, those films are used as diffusion barrier layers between Cu and Si. TiN and ZrN films have usually been deposited at high temperature in the hope of lowering the stress, increaseing the bonding strength between films and substrates, optimizing grains of films and attaining higher microhardness. So that a lot of experiments have been done at high temperature, but there are a little researchs preparing those films at room temperature. The deposition temperature determines the range of the substrates and the meaing of deposition at room temperature is more substrates which are not available at high temperature can be employed, such as the soft organic substrates, which leads not only to expand the potential utility of those films, but to a simple deposition process with lower energy consuming. With the development of the industry, the films with pure compostion can't satisfy the needs of practical application, so that doping, which results that the color, mechanical, chemical and optical properties of films are bound to change with the varieties and the quatities of doping materials, is ment to be. Zr-doping improves not only the mechanical properties of TiN films, but also better corrosion resistance of TiN films due to the excellent corrosion resistance of Zr element. TiN and (Ti,Zr)N films have been deposited on the slides and metal substrates with pure Ti and Zr targets in this case. The effect of process parameters on mechanical and optical properties and structure of TiN films, and the effect of Zr-doping on the characterizations and structure of (Ti,Zr)N films are discussed via spectrophotometer, XRD and STM methods. The transparent hard films have been prepared by RF magnetron sputtering and the properties of those films have also been studied. The results showed that the TiN and (Ti,Zr)N films are polycrystalline phase. The properties and structure of TiN films are mainly determined by the N2 mass flow rate, and as the N2 mass flow rate increases, the structure of the TiN films transforms to f.c.c. type leading to better the properties of films. The presence of negative bias voltage can optimize the grain of TiN films, lower the defect proportion and denser the films, which improves the hardness of films. The TiN films conform to the free carrier absorption mechanism and there are many of free electrons with lower N content in TiN films. With the increase of N content, the quantity of free electrons and reflectivity of films decrease, and the plasma frequence shifts to the lower energy, which leads to the regular change of colors of films from silver, yellowy, golden to yellow-red, meanwhile the lightness of films decreases. The golden (Ti,Zr)N film consists of TiN and ZrN phase, but belongs to a sigle f.c.c. structure with (111) preferred orientation. The Zr-doping dosen't change the position of the valance band, conduction band and forbidden band of (Ti,Zr)N film, but leads to the presence of new energy levels, which is the reason that (Ti,Zr)N film remains golden. The transparent hard films with good corrosion resistance and high hardness have been prepared and the further reseachs showed that the grain size of those films is by far smaller than the wave length and the width of forbidden band of those films is very broad, is the reasons that those films are transparent.