Nucleation in the initial stage of hydrogenated microcrystalline silicon (mu c-Si:H) film deposition by VHF inductivity-coupled plasma (ICP) has been investigated. When the SiH4 concentration (R-SiH4=[SiH4]/([SiH4]+[H-2])) is 6%, the crystallization in the initial 1.1-2.4 nm film deposition is observed at the substrate temperature of 320 degrees C, while it is decreased to 150 degrees C by reducing the R-SiH4 to 3%. Furthermore, the nucleation is significantly promoted by H-2 plasma pretreatment as long as 90 s prior to mu c-Si:H film deposition. The crystallinity was improved from 33 to 54% and the grain density was increased from 8.0 x 10(10) to 1.7 x 10(11) cm(-2) by the pretreatment. We confirmed no significant change in SiO2 surface micro roughness after the H-2 plasma pretreatment. The chemical bond states at the SiO2 surface before film deposition play an important role in nucleation. (C) 2007 Elsevier B.V. All rights reserved.