Plasma Dynamics of RF Multi-Trench Hollow Cathode Discharge using Hybrid Plasma Model

A two-dimensional hybrid plasma model (fluid ion and kinetic 2D-3V PIC electron) is used to study a capacitively coupled radio-frequency (RF) discharge where the powered electrode has an array of four hollow tapered trenches. The operating voltage at 13.56 MHz of the powered electrode is varied. The plasma dynamics in terms of electron power deposition, electron energy and plasma generation leading to plasma density are evaluated. The excitation rate and Ar* density distributions during RF cycle are illustrated. The geometrical properties (angle, height and spacing) of one of the four tapered trenches are varied to study their effect on plasma properties such as the uniformity of plasma density, ionization rate and power deposition. A 2D moment analysis approach is used to compute each term of the fluid conservation equations (continuity, momentum and energy) for the electrons using the kinetic data to study the relative importance of the terms. The power absorbed by the electrons due to collisionless and ohmic heating, during an RF cycle and their relative importance under different conditions will be presented.