SiOx (x<2) films were deposited in an O2 atmosphere using Si target in a pulsed laser deposition system. Post-annealing process was employed in an O2 atmosphere to form the nanometer-sized Si crystallites embedded in the SiO2 films. The transmission electron microscope analysis shows the existence of crystalline silicon nano-dots with diameters ranging from 2 to 4 nm. Also, the clear separation of Si and SiO2 phases can be seen in the X-ray photoemission spectra. Photoluminescence peak from the annealed films was obtained, which is attributed to the quantum confinement effect of the Si nano-dots. C-V measurements of the metal-oxide-silicon (MOS) structure containing the silicon nano-dots in the oxide layer were performed to investigate the charging/discharging behavior of the silicon nano-dots. The maximum program window of the MOS was measured to be4.1V under ±5V sweep.