Suppressing Ambipolar Current in UTFET by Auxiliary Gate

In this paper, a new U-shaped channel tunneling-based field-effect transistor (UTFET) with auxiliary gate above drain is proposed. The ambipolar current in the proposed is investigated, in which simulation results show that ambipolar current takes place, due to drain-to-drain tunneling similar to gate-induced drain leakage in conventional MOSFETs. By drain depletion in auxiliary gate-based UTFET, electric field is reduced in ambipolar tunneling region, which causes tunneling barrier width to increase and the energy window of tunneling (Delta phi) to decrease. As a result, two decades of reduction in the ambipolar current is achieved and ambipolar subthreshold swing (SSamb) is degraded by 24.8% in comparison with similar structure without auxiliary gate.