Simulations of a triode system with an internal grid

Summary form only given. The 2D particle-in-cell code PDP2 has been modified to include internal structures for modeling a triode system with an internal grounded grid. The triode system includes one or two driven electrodes, an internal grounded grid and grounded walls. The wafer is placed on a driven electrode and biased to extract ions from the plasma. Ion impact secondary electron emission from the walls and the grid is also included in order to allow for possible hollow cathode effects. In our simulations, we only bias the target electrode and ground the other electrode. We use argon as the background gas at pressures of 20-50 mTorr. The external RF voltage source is set to be near 1 kV, and the target bias voltage is obtained self-consistently to be near the RF voltage. We investigate the plasma with and without the grid and the secondary electrons to understand their role in plasma creation, ion flux uniformity and resulting ion energy distribution at the biased target. We also vary the grid spacing and location to find the optimum plasma density and ion flux uniformity.