Theoretical investigation of sheath expansion and implant fluence uniformity in enhanced glow discharge plasma immersion ion implantation

In enhanced glow discharge plasma immersion ion implantation that involves a small-pointed anode and large area tabular cathode, the high negative substrate bias acts as the plasma producer and supplies the implantation voltage. An electric field is created to focus the electrons and the electron-focusing field in turn enhances the glow discharge process. The sheath physics is theoretically investigated using numerical simulation based on the multiple-grid particle-in-cell code. Electron focusing is corroborated and the plasma sheath has enough expansion when t=40μs so that a uniform distribution of the incident ion fluence is attained.