Experimental and simulation study of a capacitively coupled radiofrequency plasma with a structured electrode

Abstract A low-pressure capacitively coupled radiofrequency (RF) helium discharge with a structured electrode is investigated experimentally and via kinetic simulations. In the experiment, phase resolved optical emission spectroscopy provides information about the excitation dynamics by high energy electrons, with high spatial and nanosecond temporal resolution within the RF (13.56 MHz) period. The numerical studies are based on a newly developed 2d3v particle-in-cell/Monte Carlo collisions code carried out on graphics processing units. The two approaches give consistent results for the penetration of the plasma into the trench situated in one of the electrodes and the particular electron dynamics resulting from the presence of the structured electrode. In addition, the fluxes of He + ions and vacuum ultraviolet photons incident on the different surfaces in and around the trench structure are studied. These are discussed with respect to the homogeneous treatment of complex structures, relevant for advanced surface modification and disinfection processes.