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

A pulse modulator for plasma-based ion implantation (PBII) has been newly developed and the current capacity is improved in comparison with the previously developed hard tube modulator. The modulator is characterized by two-switch operation. A rectangular shape of the voltage waveform is obtained even for a capacitive load. Two hard-tubes as a main switch are used in parallel to increase the current capacity and another two hard-tubes are used for releasing the charge of the capacitors in the circuit after the end of the pulse. The current capacity is 20 A during the pulse at an output voltage of 40 kV. The pulse width is varied from 2 to 100 μs under a maximum repetition rate is 2.5 kHz