Articolo in rivista, 2014, ENG, 10.1088/0963-0252/23/6/065049

Radio-frequency capacitively coupled plasmas in hydrogen excited by tailored voltage waveforms: comparison of simulations with experiments

Diomede, P.; Economou, D. J.; Lafleur, T.; Booth, J-P; Longo, S.

University of Houston; Ecole Polytechnique; National Office for Aerospace Studies & Research (ONERA); CNR-IMIP and University of Bari

A combined computational-experimental study was performed of a geometrically symmetric capacitively coupled plasma in hydrogen sustained by tailored voltage waveforms consisting of the sum of up to three harmonics. Predictions of a particle-in-cell with Monte Carlo collisions/fluid hybrid model were in reasonably good agreement compared to data from an array of experimental plasma diagnostics. The plasma was electrically asymmetric, with a dc self-bias developed, for all but a sinusoidal voltage waveform. Hydrogen ions (H+, H-2(+), H-3(+)) bombarding the electrodes exhibited different ion flux-distribution functions due to their different masses and collisionality in the sheath. Plasma density, ion flux and absolute value of the dc self-bias all increased with increasing the number of harmonics. The energy of ions bombarding the substrate electrode may be controlled by switching the applied voltage waveform from (positive) 'peaks' to (negative) 'valleys'.

Plasma sources science & technology (Print) 23 (6)

Keywords

capacitively coupled plasmas, tailored voltage waveforms, hydrogen plasmas

CNR authors

Longo Savino

CNR institutes