Study of space voltage distribution between large-area parallel-plate electrodes for very high frequency plasma enhanced chemical vapor deposition

The two-dimensional quasi-planar circuit model is used to study the space voltage distribution between large-area parallel-plate electrodes of very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) reactor. The results show that the voltage standing wave effects become the important factor affecting non-uniform voltage distribution when the electrode dimensions and excitation frequency are increased. For a large-area parallel-plate electrode with 1.2 m by 0.8 m lateral dimension, driven respectively at frequencies of 40.68 and 60 MHz, the space voltage non-uniformity about +/- 2.5% and +/- 5.5% are obtained by optimization of the number and position of the power feeding points. These results provide important theoretical guidance for large-area parallel-plate electrodes used for VHF-PECVD.