Fabrication and charging characteristics of MOS capacitor structure with metal nanocrystals embedded in gate oxide

Metal-oxide-semiconductor capacitor structure with metal nanocrystals embedded in the gate oxide for the application of nonvolatile memory ( NVM) is fabricated. Optimal process parameters are investigated and Au nanocrystals are adopted in this paper. High-frequency capacitance versus voltage ( C-V) and conductance versus voltage ( G-V) measurements demonstrate the memory effect of the structure which is shown to originate from the confined states of metal nanocrystals. Capacitance versus time ( C-t) measurement under a constant gate bias is executed to evaluate the retention performance and an exponential decaying trend is observed and discussed. It is found that with respect to semiconductor counterparts, Au nanocrystals can provide enhanced retention performance, which confirms the high capacity of Au nanocrystals for NVM applications.