The influence of the negative substrate bias on the interfacial and microstructural characteristics of nanocrystalline silicon (nc-Si) thin films was deposited by hot wire chemical vapor deposition (HWCVD). Structural characterization of nc-Si films was performed by small angle X-ray diffraction (SAXRD), Raman spectroscopy, X-ray reflectivity (XRR) and field emission scanning electron microscopy (FESEM). Crystalline fraction and crystallite size increases from 61.31 to 74.13% and 13.3 to 21.6nm, respectively, with an increasing negative bias from 0 to −200V. Furthermore, the deposition rate of nc-Si films increases from 25 to 68nm/min by increase of negative substrate bias from 0 to −200V.