OFF-State Leakage Suppression in Vertical Electron-Hole Bilayer TFET Using Dual-Metal Left-Gate and N⁺-Pocket

In this paper, an In_0.53Ga_0.47As electron-hole bilayer tunnel field-effect transistor (EHBTFET) with a dual-metal left-gate and an N⁺-pocket (DGNP-EHBTFET) is proposed and systematically studied by means of numerical simulation. Unlike traditional transverse EHBTFETs, the proposed DGNP-EHBTFET can improve device performance without sacrificing the chip density, and can simplify the manufacturing process. The introduction of the dual-metal left-gate and the N⁺-pocket can shift the point-tunneling junction and adjust the energy band and the electric field in it, aiming to substantially degrade the OFF-state current (I_OFF) and maintain good ON-state performance. Moreover, the line tunneling governed by the tunneling-gate and the right-gate can further regulate and control I_OFF. By optimizing various parameters related to the N⁺-pocket and the gate electrodes, DGNP-EHBTFET's I_OFF is reduced by at least four orders of magnitude, it has a 75.1% decreased average subthreshold swing compared with other EHBTFETs, and it can maintain a high ON-state current. This design greatly promotes the application potential of EHBTFETs.