Fine Structure of Ionisation Patterns and Confinement of Energetic Electrons in Asymmetric Capacitive Radio Frequency Discharges

Sebastian Wilczek, Jan Trieschmann, Julian Schulze, Ralf Peter Brinkmann, Donkó, Zoltán, Thomas Mussenbrock

ICPIG 2017, Estoril/Lisbon, Portugal, July 9-14


Geometrically asymmetric capacitively coupled radio frequency discharges (CCRF) are investigated by Particle-In-Cell (PIC) simulations. At low pressures, CCRF discharges promote strongly nonlinear dynamics and nonlinear electron resonance heating (NERH) is important. During sheath expansion, multiple electron beams are accelerated into the plasma bulk, which support the ionization process and frequently lead to the excitation of the plasma series resonance (PSR). At small gap sizes and low pressures, some of these beam electrons can reach the opposing sheath at different temporal phases without any collisions. Especially during sheath collapse, the confinement of these energetic electrons is inefficient, which influences the complete discharge.