Particle-in-cell simulation of an electronegative plasma under direct current bias studied in a large range of electronegativity

International audienceA one-dimensional electronegative plasma situated between two symmetrical parallel electrodes under DC bias is studied by Particle-In-Cell simulation with Monte Carlo Collisions. By varying the electronegativity α ≡ n−/ne from the limit of electron-ion plasmas (negative ion free) to ion-ion plasmas (electron free), the sheaths formation, the negative ion flux flowing towards the electrodes, and the particle velocities at the sheath edges are investigated. Depending on α, it is shown that the electronegative plasma behavior can be described by four regimes. In the lowest regime of α, i.e., α 10⁵, the presence of electrons in the plasma is marginal and the electronegative plasma can be considered as an ion-ion plasma (electron free)