Preparation Of Ultrathin TiN Films Electrode By Magnetron Sputtering

TiN films that the stoichiometric ratio is close to1:1, have many fine features such as simple preparation process, inexpensive, good conductivity and high work function, so it become one of the mainstream electrode materials in the microelectronics industry, widely used in the devices like DRAMand FET. When TiN films are in contact with high-k dielectric layer, it can form high schottky barrier, which can made the devices smaller intrinsic leakage flow, helpful to reduce the power consumption, and at the same time improve the reliability. In addition, in the study of new ferroelectric material HfO2recently, researchers have found that TiN has the mechanical clamping function on HfO2as the top electrode, which will promote HfO2form metastable phase during annealing, this is crucial for HfO2to produce ferroelectric properties and stability.In this paper, TiN conductive films were deposited by DC vacuum magnetron sputtering on p-Si (100) substrates. During the experiment, it used ellipsometer and XRR to measure the thickness of the films. The resistivity of films was characterized by using four-probe measure apparatus, and the surface topography and surface roughness of TiN films were measured by SEM and AFM. XPS detected the content of different elements of TiN films and that also reflected the combination situations of chemical bonds. In this paper, the influence of sputtering current, the total pressure, target-substrate distance, substrate temperature, Ar/N2and sputtering time on color, thickness, resistivity, crystal orientation and micro-structural morphology were investigated. Through the basic parameters optimization, the ultrathin TiN nano-film electrodes were stablely and repeatably prepared with good electrical properties.The results showed that:the best preparation parameters were as follows, the pressure of0.3Pa, the sputtering current of0.35A, Ar/N2of12:1, substrate temperature of350℃and the target-substrate distance of93mm. XPS shows the stoichiometric ratio of Ti and N is close to1:1. All films are belong to polycrystalline films, the preferred orientation of which are TiN(200) and TiN(111), and the more greater1(200) is, the conductivity of films will be better. AFM shows that the surface of films is more level and smooth, and there is not obvious grain growth.