Abstract
A study has been made on the effect of He dilution on the stmcture and photoconductivity of hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films prepared by RF plasma CVD method using SiH4 and C2H2 as source gases. The concentration of SiH2 and CH bonds in the films decreases and the deposition rate increases due to the He dilution. The film density increases with decreasing the concentration of SiH2 and CH bonds. The photoconductivity is enhanced with an increase in the film density. The dense a-Si1-xCx:H films of x = 0.2 have high photoconductivity (ημτ = 10-6 cm2/V) as the a-Si:H. The energy transfer of He atoms in the metastable states to the growing surface during deposition seems to play the most important role in obtaining dense films.
