Triggerless shunting arc generation and pulsed ion extraction

Summary form only given. Shunting discharge is an alternating capacitor discharge through a rod of solid-state materials. Optimization of the discharge condition has realized self-ignition of the arc discharge with low input power to the rod, leading to a much longer rod life time than in conventional shunting arc or peripheral arc. The shunting-arc-produced plasma contains mainly the ions of the solid-state material, and ion extraction from the plasma has also been demonstrated. Thus, the shunting arc works as a pulsed ion source for solid-state materials for plasma-based ion implantation (PBII) and ion processing. This article describes the characteristics of pulsed carbon shunting arc, using coaxial electrodes. The shunting arc current showed a damping oscillation with a peak current of 4.0 kA at 15 /spl mu/s, for the circuit parameters in the present experiment. Hesitations of arc ignition for some 2-3 /spl mu/s accompanied by voltage jump was observed at the beginning of each half cycle, which is an indication that an increase in carbon vapor pressure or emission of thermoelectrons around the rods due to rod heating is a basic requirement for the arc ignition.