The intention is to clarify characteristics of a cluster-free
amorphous silicon film which is practically produceable without incorporation of large clusters having a size of 1 nm or more, and provide a method and an apparatus for producing the
amorphous silicon film. In the cluster-free amorphous
silicone (a-Si:H) film, an in-film Si—H2
bond density is 10−2 atomic % or less, and an in-film
volume fraction of the large clusters is 10−1% or less. The a-Si:H film is produced by depositing, on a substrate, a deposition material in a
plasma flow of any one of a
silane gas, a
disilane gas and a gas obtained by diluting a
silane or
disilane gas with one or a combination of two or more selected from the group consisting of
hydrogen, Ar, He, Ne and Xe. The a-Si:H film has prominent characteristics, such that: a light-induced defect density is reduced from 2×1016 cm−3 or more in conventional a-Si:H films to substantially zero; a stabilized efficiency (%), i.e., a light-
energy conversion efficiency, is increased from 9% at the highest in existing a-Si:H films up to 14% or more; and a light-induced degradation rate, i.e., [(initial efficiency−stabilized efficiency) / initial efficiency]×100%, is reduced from 20% at the lowest in the existing a-Si:H films to substantially zero.