P3I: a simulation code for Plasma Immersion Ion Implantation (PIII) dose prediction

Abstract

Plasma Immersion Ion Implantation (PIII) is a versatile material processing technique [1] , [2] with many applications in semiconductor doping and micro- and nano- fabrication [3] , as well as the surface modification of metals for improved resistance against wear and corrosion. In PIII a solid target is immersed in plasma, and negative polarity high voltage (typically 1-20 kV) pulses are applied to the target. During a negative-polarity PIII pulse electrons are repelled from the region near the target, resulting in a positive ion sheath surrounding the target; ions traversing the sheath are implanted into the solid target surface. PIII can provide uniform ion implantation with high ion fluences across broad area targets. The targets need not be planar as the plasma is conformal to the immersed target. For precision PIII processing it is important to accurately predict the implanted ion concentrations. To this end, the P2I code was developed by Bradley, Steenkamp, and Risch [4] , [5] to accurately predict PIII sheath dynamics, ion implantation currents, and total delivered ion fluences. The P2I code is an efficient implementation of the numerical solution of Lieberman's dynamic sheath model [2] with assumptions of quasi-static ion motion and sheath position, collision less ion flow, inertia less electrons and an infinite plasma ion reservoir.