Electrical Characteristics And TiN Film Deposition Of Plasma Assisted Magnetron Sputtering

Magnetron sputtering (M.S.) techniques have been widely used in the industries due to their high deposition rate and low processing temperature. Among these techniques, plasma assisted magnetron sputtering has been paid much attention because of its higher metal ionization and plasma density. In this paper, the electric characteristics of the magnetron sputtering power supply assisted by radio frequency (RF) power source or hot filament were investigated. TiN films were also deposited on stainless steel by RF assisted DC magnetron sputtering, and the films properties, including structure, thickness, hardness, wear resistance and corrosion resistance were also studied.The results show that with the constant current mode of magnetron sputtering, the discharge voltage can be decreased with increasing the RF power or the anode current. The effect of the RF on discharge voltage is more evident than that of the hot filament plasma. With increasing the gas pressure, the discharge of effective second electron can be enhanced, as well as the decrease of discharge voltage. The improvement of the bias voltage shows more influence on the plasma, resulting in the enhancement of the discharge voltage. At the same time, the introducing of the RF can effectively decrease the influence of the bias on the discharge voltage. When the assisted plasma is employed, the I-V curves of the magnetron sputtering move down, though the trend is slightly influenced. And increasing the distance of the Ti target and the stainless steel target can also decrease the influence on the discharge voltage. N2 gas percent shows reverse influence on the Ti target and the stainless steel target due to their different second electron discharge coefficient during the reactive magnetron sputtering. And the difference is more evident with the introduction of the RF.The (111) growth orientation for TiN tends to be obtained at high gas pressure. And as the gas pressure increased, the deposition rate increases firstly, and then decreases with further increment of pressure. Under the same working pressure, the deposition rate of the RF assisted M. S. process is higher than that of single M. S. process. The hardness of TiN films is improved obviously under high gas pressure, especial for the sample deposited at 0.9Pa. The corrosion resistance of the M.S. TiN films is enhanced with increasing the gas pressure from 0.3 Pa to 0.6 Pa, but slightly depressed from 0.6 Pa to 0.9 Pa. In contrast, the corrosion resistance of the films deposited by RF assisted M.S. is enhanced by increasing the gas pressure. Good wear resistance of the films with low friction coefficient of 0.2~0.4 after long time wear test has been achieved by deposited at low gas pressure.Under low bias voltage, the growth orientation of TiN grains is (220). As the bias voltage increased further, TiN grains with (111) growth orientation can be found in the films. The deposition rate and corrosion resistance of M.S. TiN films increase with increasing the bias voltage from 80V to 200V, and then decrease. In addition, good wear resistance and higher hardness of the films treated at low bias voltage have been yielded. However, as RF assisted power is applied, finer TiN grain in the films and higher deposition rate are obtained. Moreover, low bias gives rise to better corrosion and wear resistance.