Ambipolar conduction behavior on high performance schottky barrier source/drain gate-all-around si nanowire nonvolatile SONOS memory

A Novel structure and high performance of the Schottky barrier source/drain gate-all-around (GAA) poly-Si nanowire (SiNW) nonvolatile silicon-oxide- nitride-oxide-silicon (SONOS) memory cell is reported with transistor characteristics, efficient programming/ erasing, and reliability. The non-uniform thermal stress distribution on SiNW channel due to thermal insulation from the substrate by the buried oxide layer could affect carrier transport behavior. Under a high lateral electric field, the impact ionization is found since a large lateral field enhances carrier velocity. As gate voltage increases, the difference of the drain current between higher and room temperatures can be reduced because a high gate field lowers the Schottky barrier height of source/drain to ensure a strong hot-carriers generation. In particular, the ambipolar conduction of the Schottky barrier source/drain devices promotes the amount of hot-electron injecting programming by positive gate voltage, whereas the Schottky barrier enhances the generation of hot-holes at negative gate voltage to carry out erasure. The proposed Schottky barrier SONOS memory device provides low-voltage and high efficiency programming/erasing without apparent degradation of data retention and 10-K cycling endurance.