COULOMB-BLOCKADE EFFECTS IN EDGE QUANTUM-WIRE SOI-MOSFETS

The edge of a thin SOI (silicon on insulator) film was used to form a very narrow Si-MOS inversion layer. The ultra-thin SOI film was formed by local oxidation of SIMOX wafer. The thickness of the SOI film is l ess than 15 nm, i.e., the channel width is narrower than 15 nm. At low temperatures, clear and large conductance oscillations were seen in t his edge channel MOSFET. These oscillations are explained by Coulomb b lockade effects in the narrow channel with several effective potential barriers, since the SOI film is so thin that the channel current is s eriously affected by small potential fluctuations in the channel. Thes e results suggest that the channel current in edge quantum wire MOS FE T can be cut off even with a small controlled potential change. Furthe rmore, we fabricated a double-gate edge channel Si-MOSFET. In this dev ice, the channel current can be controlled in two ways. One way is to control the electron number inside the isolated electrodes. The other way is to control the threshold voltage of MOSFET. This device enables us to control the phase of Coulomb oscillation.