Effects of Sputtering Power, Working Pressure, and Electric Bias on the Deposition Behavior of Ag Films during DC Magnetron Sputtering Considering the Generation of Charged Flux

Effects of sputtering power, working pressure, and bias on the growth rate, crystallinity, and resistivity of Ag thin films deposited by direct current (DC) magnetron sputtering were investigated. Thin films were deposited on the substrate under the electric biases of − 300, 0, and + 300 V for 30 min with sputtering powers of 20, 50, 100, and 200 W and working pressures of 2.5, 5, 10, and 20 mTorr. Under all sputtering powers, the growth rate of the thin film was increased by the positive bias, whereas it was decreased by the negative bias. For example, the film thicknesses were 345.7, 377.9, and 416.0 nm at − 300, 0, and + 300 V, respectively, at a sputtering power of 100 W and a working pressure of 2.5 mTorr. The bias effect was enhanced as the working pressure decreased. Considering the change of the film growth rate according to the bias, the amount of negatively charged flux was estimated to be roughly 10%. As the working pressure decreased, the crystallinity of the deposited films increased by the positive bias whereas it decreased by the negative bias, which is indicated by the full width at half maximum (FWHM) determined by X-ray diffraction of the Ag (111) peak. The film resistivity had the same tendency. This change in the deposition behavior of the Ag film can be understood as the effect of the charged flux.