Transient sheath in a small cylindrical bore with an auxiliary electrode for finite-rise-time voltage pulses

Summary form only given. Previous work concentrated on the determination of the ion-matrix sheath and the temporal evolution of the plasma sheath in a small cylindrical bore for zero-rise-time voltage pulses during plasma immersion ion implantation (PIII). Because realistic voltage pulses have a finite rise time, this paper addresses the temporal evolution of the plasma sheath in a small cylindrical bore with an auxiliary electrode for different rise times by solving Poisson´s equation and the equations of ion continuity and motion numerically using the appropriate boundary conditions. The ion density, flux, dose, energy, energy distribution, and average impact energy on the surface of the target for different rise times are determined and compared to the case when the auxiliary electrode is absent. Our results predict a substantial improvement of the impact energy during PIII of a cylindrical bore when an auxiliary electrode is employed even for finite-rise-time voltage pulses.