New Results of nc-Si:H Films Prepared by Hydrogen-Diluted Silane in a Triode Pecvd System

Abstract

AbstractWe report new results on microstructures and electronic properties of nanocrystalline silicon (nc-Si:H) films prepared by a triode PECVD method with a hydrogen diluted silane plasma. The transition from a-Si:H to nc-Si:H was obtained by varying the ratio of H2 to SiH4 while the bias of the grid electrode was fixed at 100.V with respect to the substrate. The threshold value of [H2]/[H2 ]+[SiH4] is about 93.3%. With increasing value of [H2]/[H2]+[SiH4], the volume fraction of crystallinity in nc-Si:H films increased from 12% to 50%, while the average grain size remaind constant. This is quite different from the structures of samples prepared by the conventional diode PECVD with H2 dilution. The traveling-wave technique was applied to study the transport properties of nc-Si:H films, and experimental results confirmed percolation transport in nc-Si:H films.