Random capacitance modulation due to charging/discharging in Si nanocrystals embedded in gate dielectric

In this paper, we report a study on time-domain capacitance characterization of metal-oxide-semiconductor (MOS) structures with Si nanocrystals (nc-Si) distributing throughout the gate oxide. A drastic reduction of MOS capacitance can be observed by charge trapping in nc-Si, while release of the charges leads to the recovery of the capacitance. Such capacitance modulation is explained by an equivalent circuit in terms of the change of nc-Si capacitance as a result of charging/discharging. As the capacitance modulation represents a change in the electrical states of MOS structure, it could be used for memory applications.