Regular Article

PIC simulations of capacitively coupled oxygen rf discharges^★

¹ Institute of Physics, Ernst-Moritz-Arndt-University Greifswald, 17489 Greifswald, Germany
² Nuremberg Institute of Technology, 90489 Nuremberg, Germany
³ Institute of Computer Science and Technology, University Rostock, 18051 Rostock, Germany

^a e-mail: pm101481@uni-greifswald.de

Received: 31 August 2017
Received in final form: 13 November 2017
Published online: 22 May 2018

Abstract

Capacitively coupled discharges with a radio-frequency operated voltage (ccrf) are important for plasma assisted material processing. Experiments with electronegative oxygen ccrf discharges show a high-energy peak in the energy distribution of negative ions arriving at the anode, depending on the cathode material used. One possible explanation is ionization at or close to the surface of the cathode for the production of negative ions. By introducing an additional surface ionization model into a Particle-In-Cell (PIC) simulation with Monte Carlo Collisions (MCC) the experimental result is reproduced qualitatively. Comparison of one dimensional and two dimensional simulation results allows an improved understanding of the microscopic processes determining the dynamics of negative ions.