Segmented Electrode Plasma Source with Anti-Phase Discharge

A new plasma source concept, consisting of segmented electrodes and an economical 13.56 MHz power generator, has been developed for the plasma-enhanced chemical vapor deposition (PECVD) of microcrystalline silicon thin films on large-area substrates. Using a plurality of rectangular column-type electrodes fed with RF (13.56 MHz) at various relative phases, a two-stage plasma, which consists of an upper and lower plasma, was generated. In the case of supplying the anti-phase RF, we could control the ion incident energy on a substrate to be lower, so as to keep the high crystallinity and high deposition rate during the film growth. The agreement between the observed light emission profiles from Ar or Ar/H2 plasma and the numerically calculated ones was good, confirming the accuracy of the simulation model, and we performed the thin-film growth of microcrystal silicon with this new plasma source and H2/SiH4 gas. Consequently, we could achieve a fast deposition rate of more than 1.5 nm/s with good crystallinity over 60%.