Feature of electron energy distribution in a low-pressure capacitive discharge

Abstract

The evolution of the electron energy distribution function is investigated in the low-pressure capacitive discharge under the collisionless electron heating regime, where the electron mean-free path is comparable to or larger than the system length. As the gas pressure decreases from 50 to 10 mTorr, a different feature of electron energy distribution with a plateau in the low-energy electron range, indicating the strong electron heating in that energy range, is found. This observed result can be explained in terms of collisionless heating from the interaction between the electron bouncing motion and the oscillating sheath [Y. M. Aliev, I. D. Kaganovich, and H. Schuter, Phys. Plasmas 4, 2413 (1997)]. A simple calculation of the electron energy distribution with the energy diffusion coefficient, including the electron bounce effect, is in good agreement with the experiment.