An In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As Heterojunction Dopingless Tunnel FET With a Heterogate Dielectric for High Performance

In this paper, an In0.53Ga0.47As/In0.52Al0.48As heterojunction dopingless tunnel field-effect transistor (HDL-TFET) with an HfO2/SiO2 heterogate dielectric is proposed, where the N+-pocket with variable electron concentration can be formed by adjusting the length of source-side channel (LSC) based on the charge plasma concept, instead of employing conventional ion implantation or dual-material gate techniques. It aims to improve the device performance and simplify the device fabrication. At the drain bias of 0.3 V, numerical simulations show that the on-state current (ION) of the HDL-TFET with LSC = 4 nm can approach ~10−5A/ $\mu \text{m}$ that is far higher than that of the Si-DL-TFET (~10−10A/ $\mu \text{m}$ ), and the average subthreshold swing (SSavg) can approach 36.6 mV/decade that is significantly lower than that of the Si-DL-TFET (89.2 mV/decade). It is also found that the drain-induced barrier lowering (DIBL) effect and the ambipolar current can be effectively suppressed in the HDL-TFET because of an existence of heterojunction. Under the condition of low gate and drain biases, the HDL-TFET exhibits peak values of the cutoff frequency (fT) and the maximum oscillation frequency (fmax) approaching 13 and 4.73 GHz, respectively, while the Si-DL-TFET yields those of 8.05 and 2.26 GHz, respectively, under relatively higher biases. It indicates that the HDL-TFET is a promising device for low-power consumption radio frequency applications.