A two-switch mode pulse modulator for plasma-based ion implantation and deposition

A new-concept pulse modulator was developed for a plasma-based ion implantation (PBII) system, where two hard-tubes as a main switch are running in parallel to increase current capacity for outputting the pulse voltage and another two hard-tubes are used for releasing the charges stored in the stray and ion sheath-capacitor. A maximum output voltage is 40 kV with an average current of 20 A, where the pulse width is varied from 2 /spl mu/s to 100 /spl mu/s. The rise time less than 1 /spl mu/s at an output voltage of 40 kV and a maximum repetition rate of 2.5 kHz.