Investigation of a differentially powered multi-tile VHF CCP using particle in cell simulation
Bosschaert, JoachimORCID: 0000-0002-1060-8285
(2023)
Investigation of a differentially powered multi-tile VHF CCP using particle in cell simulation.
Master of Science thesis, Dublin City University.
A differentially powered, very high frequency (VHF), multi-tile, capacitively coupled plasma system is modelled using particle in cell simulation code, Xoopic [2]. The powered electrode in this system is split into an array of differentially powered tile. The current path is observed in the plasma; one pathway is towards the opposite grounded boundary; a second pathway is observed coupling between adjacent out-of-phase tiles (coupled current). Two physical phenomena are de- scribed that could drive the coupled current; An electrostatic phenomenon, due to a spatio-temporal variation in the plasma potential. And an electromagnetic phenomenon, due to a time-varying magnetic dipole between adjacent tiles that induces an electric field. Through solving Generalized Ohm’s Law in the plasma system, and calculating the magnitude of the induced electric field, it is deter- mined that the electrostatic mechanism is the dominant mechanism for driving the coupled current.
A region of higher plasma density is identified in front of the powered electrode. This region also supports a higher electron temperature and ionization rate. Most of the current in this region points from one electrode to the adjacent electrode. Towards the grounded electrode plasma density, electron temperature and ionization rate are lower and most of the current points towards the substrate. As driving current is increases, a larger fraction of driving current moves towards the adjacent tile rather than towards the grounded electrode.