Abstract: The optimized process parameters for the formation of metal nanocrystals are investigated.Ag nanocrystals with the mean size of 8nm and density of 5×10¹¹/cm² are obtained.Also,the disperse and the shape of the nanocrystals are uniform and spherical.MOS capacitor structure with Ag nanocrystals embedded in gate oxide is fabricated.The electrical characteristics is investigated through high-frequency capacitance versus voltage（C-V） and conductance versus voltage（G-V） measurements,which is shown that the memory effect mainly originates from the confined states of metal nanocrystals.Normalized capacitance versus time（C-t） curve follows to an exponential decaying law.It is observed that the retention time is 290s,which suggests Ag nanocrystals can provide enhanced retention performance.