  Metal-nanoclusters (NC), deposited by magnetron-based nanocluster source
coupled with quadrupole mass filter (QMF) assembly having independent control
over its size and density, are used in fabricating NC-based non-volatile memory
(NVM) devices. The effect of diameter and density on the NVM charge storage
characteristics are presented where Ag is used as the metal NC. The Ag-NC,
sandwiched between HfO$_2$ tunnel and control oxides, is deposited by using the
combination of the above two instruments. No annealing is performed at any
stage of the device fabrication. The largest hysteresis loop area in the
capacitance-voltage ($C-V$) characteristics of metal-oxide-semiconductor (MOS)
characteristics is observed for a cluster density of 1 $\times$ 10$^{11}$
cm$^{-2}$. Further, an NC size dependent hysteresis loop area is observed with
the MOS devices where the NC diameter is varied from 3 to 1.5 nm keeping the NC
density at 1 $\times$ 10$^{11}$ cm$^{-2}$. The device performance is found to
be improved with a reduction of the NC size and shows its best with the NC
diameter of 1.5 nm. The storage time of the NVM devices also increases with the
decrease in the NC diameter and exhibits their best performances for the NCs
with a diameter of 1.5 nm.
