High power modulator for plasma ion implantation

The treatment of metal and polymer materials by plasma ion implantation (PII) requires high‐voltage, high average‐power modulators to process relatively large‐size parts in a reasonable amount of time. CROSSATRON‐switch‐based modulators provide all of the features desired for large‐scale PII. The fast opening and closing capability of the switch eliminates the need for pulse‐forming networks and high‐voltage thyratrons, and allows arbitrary pulse width adjustment over the range of 2 to 100 μs of interest for PII. The CROSSATRON switch is capable of modulating high peak currents, which permits rapid charging of the relatively high capacitance of the PII load to provide fast switching times. The CROSSATRON switch requires only a low‐voltage (≤1 kV) pulsed biasing of the control grid to close and open, and has switching times of 1 μs or less. CROSSATRON switches are cold‐cathode, plasma discharge devices that also eliminate the need for large filament‐heater power supplies and higher grid‐drive power require...