Discharge Properties Of Unbalanced Magnetron Sputtering System And Application Of TiN_x Films Deposition

The studies of unbalanced magnetron sputtering (UMS) has inspired great attention recently for highly ion bombardment, which can help to form higher ion-to-atom arrival ratio to deposit dense films with perfect quality. In UMS, the identification of relations between the discharge properties and deposition parameters becomes very difficult for multivariate process. The Structure-Zone-Model (SIM) includes basic parameters of film depostion. In order to model and control the discharge and deposition process the mechanism of the UMS need to be studied further to satisfy the increasing application.The magnetic field distribution is key to the properties of UMS. The unbalanced magnetron target is improved outside magnet pole, which form an unbalanced magnetic field to confine plasma, for a magnetic field gradient coming from a magnetic mirror effect.The circular plane magnetron target with a certain unbalanced degree is an Unbalanced Magnetron target in Permanent Magnet mode (PM-UMS). The system with improved unbalanced degree by additional coaxial solenoid is Coaxial Solenoid confinement Unbalanced Magnetron target (CS-UMS). The influence of the coaxial coil on the discharge and deposition properties of the unbalanced magnetron target has been studied. The parameters under the influences of different coil current, such as Paschen curves and voltage-current properties, electron temperature, plasma potential, deposition rate at the deposition position, were studied by Langmuir probe, emissive probe, planar electrode for measuring ion current and emissive spectroscopy methods. Under the influences of coaxial coil, electron temperature and the ion saturation current were increased. Coaxial magnetic field have reduced the discharge voltage on the cathode, improved the ionized efficiency and the stability of the deposition at a lower pressure.The electrode with a surface parallel to cathode measures ion flux at a bias voltage of -150V, a pressure of 0.2Pa, with argon discharge and different locations from cathode. The ion saturation current density is a function of the discharge current, coaxial coil current and substrate location. Under influence of the coaxial magnetic field the ion flux was increased froma negligible value to 9.5mA/cm2 at the location of more than 200mm from cathode, the results of experiment also show that ion flux incident to the substrate reaches saturation value and keep constant with variation of the discharge current and coil current The influence of coil on the voltage-current properties Was modeled based on Child law. By the magneto-hydrodynamic theory the ion flux as a function of discharge power, pressure and substrate location was modeled with magnetic mirror effect. The transportation of the ion and neutral particle were treated, respectively. As a result, the coaxial magnetic field improved the performance of the system. There is a fine consistency between the model and experiment results. The results can help to control the depositing parameter in quantity.By UMS, the smooth, dense and even TiNx film has been deposited at room temperature (RT). With variation of the coaxial magnetic field the incident ion-to-atom arrival ratio to the substrate (Ji/Jm ) have been studied at variation of sputtering power, bias and pressure, proportion of nitrogen-to-argon mass flow ratio (f(N2/Ar)) of depositing TiNx film. Atom force microscope (AFM) has been used to study surface roughness and the surface morphology of TiNx fihiL The structure of TiNx film was investigated by glancing angle incident X-ray diffraction method (G2XRD). The microhardometer and ball-on-disk friction was used to determine the influence on coefficient of static friction and the Knoop microhardness of deposition parameters of TiNx film. As a result, TiNx film at a bias of-50 V and with an ion-to-atom arrival ratio of 4.1 has the highest microhardness value with dense, small crystal island. f(N2 /Ar) in the range of 0.3-0.64 has better influence on the formation of deliver dense and smooth TiNx film morphology. At low temperature and low sputtering power the films trend to become deliver, dense structure with atom level smooth surface morphology. Applications of the parameter model can help to deposit film with ideal structure, performance and morphology.