Particle-in-Cell simulations of high voltage-driven low pressure capacitively coupled plasmas

In recent work [Wen et al 2023 Plasma Sources Sci. Technol. 32 064001], we presented the important role of realistic electron-induced secondary electron emission (SEE), metastable atom and photon-induced secondary electrons from electrodes on the plasma density in low pressure capacitive argon discharges at 13.56MHz. Including the surface processes, the plasma density from the kinetic particle-in-cell (PIC) simulations shows good agreement with experimental measurements [Schulenberg et al Plasma Sources Sci. Technol. 30 (2021) 105003] at low pressure (1-10 Pa). In this work, we investigated the high voltage-driven capacitive discharges at low pressure via the validated PIC model and found that the plasma density significantly increases for a small increase of background pressure. In addition, the plasma density shows a nearly linear scaling versus the driving voltage as expected for amplitude below 1000V. However, for driving voltage above 1000 V, the linear scaling breaks for low pressure discharges. The electron dynamics and the power absorption will also be analyzed in detail.