Hydrogenated amorphous silicon (a-Si:H) films were deposited by hot-filament-assisted chemical vapour deposition (HF-CVD), r.f. glow discharge CVD (GD-CVD) and their hybrid version (HF-GD-CVD). The films were characterized in terms of their structural disorder, H bonding, optical band gap and photoconductivity. These parameters for the HF-CVD films were compared with those of the GD-CVD and HF-GD-CVD films. The structural disorder in all the films was found to be mainly a linear function of the growth rate, although the degree of change varied depending on the technique used. The HF-CVD films appeared to be structurally better ordered than those of GD-CVD and HF-GD-CVD. The improved order in the HF-CVD films was attributed to the absence of charged particle bombardment and to the improved ratio of SGH species to SiH2 species. At higher growth rates, this ratio decreased and the disorder increased. At low growth rates, the structural and electronic qualities of the HF-CVD films were independent of the H content. The growth rate thus appeared to be the limiting factor in controlling the quality of a-Si:H films; this limiting value was higher in HF-CVD.