Investigation of radio-frequency sheath structure in electronegative plasma with Cairns–Tsallis electron distribution

This study investigates the behavior of a radio-frequency (RF) plasma sheath comprising electrons, positive ions, and negative ions. The sheath structure is analyzed numerically using a one-dimensional hydrodynamic model coupled to an equivalent circuit. In this model, electrons are described by a Cairns–Tsallis distribution, which accounts for both non-extensive and non-thermal characteristics. Positive ions are modeled as a fluid, while negative ions follow a Boltzmann distribution. An equivalent circuit, consisting of a diode, a capacitor, and a current source connected in parallel, is used to describe the spatio-temporal evolution of the RF sheath properties. The results show that as the electronegativity parameter decreases, the sheath structure becomes significantly influenced by the non-extensivity parameter, the non-thermality parameter, the current amplitude, the electron to negative ion temperature ratio, and the current frequency.

Graphical abstract