Optical Response of Si-Quantum-Dots/NiSi-Nanodots Stack Hybrid Floating Gate in MOS Structures
We have studied the effect of 1310 nm light irradiation on the charge distribution of a hybrid floating gate consisting of silicon quantum dots (Si-QDs) and NiSi Nanodots (NiSi-NDs) in MOS capacitors. The light irradiation resulted in reduced flat-band voltage shifts of the MOS capacitors in comparison to the shift in the dark. This result can be interpreted in terms of the shift of the charge centroid toward the gate side in the hybrid floating gate caused by the photoexcitation of electrons in NiSi-NDs and the subsequent electron tunneling to Si-QDs. The capacitance of the MOS capacitors at constant gate biases was modulated with pulsed light irradiation. When the light irradiation was turned off, capacitance recovered to its level in the dark, indicating that the photoexited charges were transferred between the Si-QDs and the NiSi-NDs without being emitted to the Si substrate and gate electrode.
Seiichi Miyazaki and Hitoshi Tabata
N. Morisawa et al., "Optical Response of Si-Quantum-Dots/NiSi-Nanodots Stack Hybrid Floating Gate in MOS Structures", Key Engineering Materials, Vol. 470, pp. 135-139, 2011