Preparation of large uniform amorphous silicon films by VHF-PECVD using a ladder-shaped antenna

We have succeeded in preparing very uniform hydrogenated amorphous Si (a-Si/H) films by VHF plasma CVD at 60 MHz using as an electrode a ladder-shaped antenna. The rf power was applied to eight loading points on the ladder-shaped antenna. In order to supply equal rf power at the each loading point, the power divider was introduced between the electrode and a matching box, which enables the distribution of the feeding rf power at the each point less than 10%. a-Si/H Films were deposited on 400×500-mm glass substrates using pure silane gas. Films produced by this method showed a uniformity of ±10% over the substrate with a high deposition rate of 1.5 nm/s.