Pressure Dependent Plasma Characteristics in an RF Capacitively Coupled DischargeAlyssa Daniel-Peterson¹, Derek C. Lamppa², Ricky Tang², Andrew Fierro¹New Mexico Institute of Mining and Technology Socorro, New MexicoSandia National Laboratories, Albuquerque, New Mexico

The effect of pressure on the plasma density and the ion energy distribution function (IEDF) for a capacitively coupled plasma in argon gas is investigated. The Particle-in-Cell (PIC), Direct Simulation Monte Carlo (DSMC) used here consists of a one-dimensional, parallel plate geometry with an RF frequency of 13.56 MHz and amplitude of 150 V applied to cm-

scale gap sizes and pressures (<600mTorr). It is observed that the plasma densities are more uniform in the center of the discharge gap at pressures between 25-200 mTorr and peaks near the electrodes with a lower density in the center as the pressure is increased. The IEDF demonstrates a narrowing of the distribution and a decrease in peak energy as pressure increases. Finally, these simulation results are consistent with experimental measurements and ultimately demonstrate the sensitivity of the plasma to changing pressure in the sub-Torr regime.