In this work, we have investigated the capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of silicon nanocrystals (nc-Si) distributed in the gate oxide very near the SiO2/Si interface of a Metal-Oxide-Semiconductor (MOS) structure. The MOS structure is found to be sensitive to only the positive voltage stress from which charging of the nanocrystals causes a negative flatband voltage shift. At the same time, a large conductance peak is observed due to the energy loss via the neutral-nanocrystal paths near the SiO2/Si interface. Besides, breakdown the dielectric film containing the nc-Si is also observed from the G - V characteristic. (c) 2005 Elsevier B.V All rights reserved.