Hydrogenated amorphous silicon nitride (a-SiN:H) films were deposited on flexible polyethylene terephthalate substrates at temperature as low as 100 degrees C by hot-wire chemical vapor deposition using SiH4, H-2 and NH3 precursors. Field emission scanning emission microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and small angle X-ray scattering were employed to study structural and microstructural properties of a-SiN:H films. Therms surface roughness increased with increase of positive bias to substrate. Intermediate range order, porosity and interface inhomogeneity in amorphous of a-SiN:H film sevaluated by acoustic and optical phonon of silicon network, Guinier plot and correlated length from Raman and SAXS characterizations. The fractal behavior of a-SiN:H domains approached the perfect symmetry and the intermediate range order of a-SiN:H films deteriorate with increase of the positive substrate bias. Both correlation length and void size of the a-SiN: H amorphous domain increased with increase of the substrate bias from 0 to + 200 V. (C) 2009 Elsevier B. V. All rights reserved.