Quantum Mechanical Study of the Germanium Electron–Hole Bilayer Tunnel FET

Abstract

The electron-hole bilayer tunnel field-effect transistor (EHBTFET) is an electronic switch that uses 2-D-2-D sub-band-to-sub-band tunneling (BTBT) between electron and hole inversion layers and shows significant subthermal swing over several decades of current due to the step-like 2-D density of states behavior. In this paper, EHBTFET has been simulated using a quantum mechanical model. The model results are compared against transactions on computer-aided design simulations and remarkable differences show the importance of quantum effects and dimensionality in this device. Ge EHBTFET with channel thickness of 10 nm results as a promising device for low supply voltage, subthreshold logic applications, with a super steep switching behavior featuring SSavg ~ 40 mV/dec up to VDD. Furthermore, it has been demonstrated that high on current levels ( ~ 40 μA/μm) can be achieved due to the transition from phonon-assisted BTBT to direct BTBT at higher biases.