A new method for the fabrication of nanocrystalline silicon (nc-Si) in SiH4 plasma with very-highfrequency (VHF; 144MHz) excitation is proposed to increase the deposition rate, to control the size, and to minimize size dispersion of nc-Si. Nanocrystalline silicon is formed in the gas phase of the SiH4 plasma cell by coalescence of radicals. Supplying Ar enhances the nucleation of nc-Si because of high efficiency of SiH4 excitation into SiH2 radicals resulting in the nucleation. The deposition rate is thus increased by a factor of 100 to 1012/cm2.h. At the low flow rate of SiH4, smaller nc-Si with small dispersion is obtained. Moreover, when pulsed-SiH4 is supplied into Ar plasma, the growth of nuclei is limited by the time when SiH4 flows. The size of nc-Si and its dispersion are adjusted by the duration of SiH4 gas pulse.