Xie Haiwu, Chen Yanning, Liu Hongxia, Guo Dan
Key Laboratory for Wide-Band Gap Semiconductor Materials and Devices of Education, The School of Microelectronics, Xidian University, Xi'an 710071, China.
The School of Physics and Electronic Information Engineering, Qinghai Normal University, Xining 810016, China.
Materials (Basel). 2021 Mar 15;14(6):1426. doi: 10.3390/ma14061426.
It is well known that the vertical tunnel field effect transistor (TFET) is easier to fabricate than the conventional lateral TFETs in technology. Meanwhile, a lightly doped pocket under the source region can improve the subthreshold performance of the vertical TFETs. This paper demonstrates a dual material gate heterogeneous dielectric vertical TFET (DMG-HD-VTFET) with a lightly doped source-pocket. The proposed structure adopts a GaSb/GaAsSb heterojunction at the source and pocket to improve the band-to-band tunneling (BTBT) rate; at the same time, the gate electrode is divided into two parts, namely a tunnel gate (M1) and control gate (M2) with work functions Φ and Φ, where Φ > Φ. In addition, further performance enhancement in the proposed device is realized by a heterogeneous dielectric corresponding to a dual material gate. Simulation results indicate that DMG-HD-VTFET and HD-VTFET possess superior metrics in terms of DC (Direct Current) and RF (Radio Frequency) performance as compared with conventional VTFET. As a result, the ON-state current of 2.92 × 10 A/μm, transconductance of 6.46 × 10 S/μm, and average subthreshold swing (SS) of 18.1 mV/Dec at low drain voltage can be obtained. At the same time, DMG-HD-VTFET could achieve a maximum f of 459 GHz at 0.72 V gate-to-source voltage (V) and a maximum gain bandwidth (GBW) of 35 GHz at V = 0.6 V, respectively. So, the proposed structure will have a great potential to boost the device performance of traditional vertical TFETs.
众所周知，在技术方面，垂直隧道场效应晶体管（TFET）比传统横向TFET更容易制造。同时，源极区域下方的轻掺杂口袋可以改善垂直TFET的亚阈值性能。本文展示了一种具有轻掺杂源极口袋的双材料栅异质介电垂直TFET（DMG-HD-VTFET）。所提出的结构在源极和口袋处采用GaSb/GaAsSb异质结以提高带间隧穿（BTBT）速率；同时，栅电极分为两部分，即具有功函数Φ和Φ的隧道栅（M1）和控制栅（M2），其中Φ>Φ。此外，通过与双材料栅对应的异质介电实现了所提出器件的进一步性能增强。仿真结果表明，与传统VTFET相比，DMG-HD-VTFET和HD-VTFET在直流（DC）和射频（RF）性能方面具有优异的指标。结果，在低漏极电压下可获得2.92×10 A/μm的导通态电流、6.46×10 S/μm的跨导和18.1 mV/Dec的平均亚阈值摆幅（SS）。同时，DMG-HD-VTFET在栅源电压（V）为0.72 V时可分别实现459 GHz的最大f和在V = 0.6 V时35 GHz的最大增益带宽（GBW）。因此，所提出的结构在提升传统垂直TFET的器件性能方面具有巨大潜力。
