Investigation of Plasma Recovery during Fall Time in Plasma Source Ion Implantation

To investigate the plasma recovery during the fall time of a high voltage pulse, a numerical model is developed by applying fluid equations for ions while assuming thermal equilibrium for electrons. In the model, effects of the circuit impedance of pulse system are taken into account. The numerical analysis reveals that the plasma recovery is affected by both the properties of plasma and internal impedance of pulse system. The experiments are conducted with a plane electrode immersed in RF-driven argon plasmas. When negative, high voltage pulses are applied to the electrode, the current and voltage waveforms are measured and compared with the simulation results. Effects of internal circuit impedance as well as plasma properties on plasma recovery during pulse fall time are discussed based on the experimental and numerical results