A symmetric heterogate dopingless electron-hole bilayer TFET with ferroelectric and barrier layers

Abstract

In this paper, a symmetric heterogate dopingless electron–hole bilayer tunnel field-effect transistor with a ferroelectric layer and a dielectric barrier layer (FBHD-EHBTFET) is proposed. FBHD-EHBTFET can not only avoid random doping fluctuation and high thermal budget caused by doping, but also solve the issue that conventional EHBTFETs are unable to use the self-alignment process during device manufacturing. The simultaneous introduction of the symmetric heterogate and dielectric barrier layer can significantly suppress off-state current (I off). Ferroelectric material embedded in the gate dielectric layer can enhance electron tunneling, contributing to improving on-state current (I on) and steepening average subthreshold swing (SS avg). By optimizing various parameters related to the gate, ferroelectric layer, and dielectric barrier layer, FBHD-EHBTFET can obtain the I off of 1.11 × 10–18 A μm−1, SS avg of 12.5 mV/dec, and I on of 2.59 × 10–5 A μm−1. Compared with other symmetric dopingless EHBTFETs, FBHD-EHBTFET can maintain high I on while reducing its I off by up to thirteen orders of magnitude and SS avg by at least 51.2%. Moreover, investigation demonstrates that both interface fixed charge and interface trap can increase I off, degrading the off-state performance of device. The study on FBHD-EHBTFET-based dynamic random access memory shows that it has the high read-to-current ratio of 1.1 × 106, high sense margin of 0.42 μA μm−1, and long retention time greater than 100 ms, demonstrating that it has great potential in low-power applications.