Thin Solid Films, Vol.292, No.1-2, 20-25, 1997
Effect of Process Parameters on Glow-Discharge and Film Thickness Uniformity in Facing Target Sputtering
The design details of a facing target sputtering system are presented. The influence of geometric parameters of the system such as target size, inter-target distance and target-to-substrate distance on the plasma discharge current and floating potential have been investigated. Also, the effect of deposition parameters, namely cathode voltage and sputtering pressure, on the plasma has been studied in detail. It has been observed that the discharge current is very sensitive to the operating pressure in the range 10 to 1 Pa for the inter target distance between 60 and 90 mm. The substrate floating potential decreased from 4 to 3 V, when cathode voltage was increased from 100 to 1000 V. For an increase of the target to substrate distance from 35 to 55 mm, the substrate floating potential increased by 1 V. A comparison of the above results with that of d.c. diode sputtering has also been presented. The thickness profiles of the films deposited at different conditions have been measured. It indicates that a large uniform thick coating could be achieved at lower inter-target distance (50-60 mm) and higher pressure (10 Pa).