EMISSION FEATURES OF A CONVENTIONAL RADIO-FREQUENCY GLOW-DISCHARGE SOURCE AND A MAGNETICALLY ENHANCED SOURCE

A side-on-viewed source was developed in order to determine spatial em ission features of a radio frequency (rf)-powered glow discharge. The discharge was formed inside a stainless steel T-shaped cell, which act ed as the grounded anode. The cathode assembly was inserted into the l eg of the T with the cathode situated near the T intersection. The res ulting plasma was formed in the long arm of the T and was viewed throu gh a window at one end of the T. Spatial profiles of Ar emission at 42 0 nm, Cu emission at 324 nm, and OH band emission at 309 nm were colle cted with an imaging spectrometer. The source was operated over a pres sure range of 0.1-1.0 torr at rf power levels between 20 and 50 W. A p ower supply was employed at frequencies of 3.5, 6.78, and 13.56 MHz in order to determine the effect of driving frequency. The source was th en modified by the placement of two magnets (either cobalt-samarium or ceramic) on its exterior. The magnets were placed on opposite sides o f the T next to the cathode in order to create a transverse magnetic f ield in the region of the discharge above the cathode surface. The eff ect of the applied magnetic field on the voltage characteristics, sput tering rate, and spatial emission features of the source were then exp lored. Detection limits of the magnetically modified source for Monel 400 samples (Ni/Cu alloy) were also determined (10-50 ppm) using a hig h-resolution photodiode-array spectrometer.