Direct Tunneling and Storage of Electrons in Ni Nanocrystals Embedded within MOS Structure

Recently, nanocrystal nonvolatile memory (NVM) devices using nanocrystals (NCs) have attracted great research interest. In this work, we investigated the feasibility of Ni nanocrystals embedded in metal–oxide–semiconductor (MOS) capacitor structure for NVM application. Ni NCs embedded in the gate oxide was fabricated. Ni nanocrystals with an average size of 7 nm and density of 1.5×1012 cm−2 were synthesized by e-beam evaporation technique followed by rapid thermal annealing. Distinct frequency-dependent capacitance peaks were observed. High-frequency capacitance versus voltage (C-V) and conductance versus voltage (G-V) measurements were also characterized. These results demonstrate that electrons can be loaded onto Ni nanocrystals by direct tunneling and can be stored in the fabricated MOS structure.