Optimization of L-shaped tunneling field-effect transistor for ambipolar current suppression and Analog/RF performance enhancement. (March 2018)

• Record Type: Journal Article
• Authors: Li, Cong; Zhao, Xiaolong; Zhuang, Yiqi; Yan, Zhirui; Guo, Jiaming; Han, Ru
• Is Part Of: Superlattices and microstructures. Volume 115(2018)
• Page Start: 154
• Page End: 167
• Publication Date: 2018-03
• Subjects: Tunneling field effect transistor -- Hetero-gate-dielectric -- Lightly doped drain -- Ambipolar current -- Analog/RF performance; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2018.01.025
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: L-shaped tunneling field-effect transistor (LTFET) has larger tunnel area than planar TFET, which leads to enhanced on-current I ON . However, LTFET suffers from severe ambipolar behavior, which needs to be further optimized for low power and high-frequency applications. In this paper, both hetero-gate-dielectric (HGD) and lightly doped drain (LDD) structures are introduced into LTFET for suppression of ambipolarity and improvement of analog/RF performance of LTFET. Current-voltage characteristics, the variation of energy band diagrams, distribution of band-to-band tunneling (BTBT) generation and distribution of electric field are analyzed for our proposed HGD-LDD-LTFET. In addition, the effect of LDD on the ambipolar behavior of LTFET is investigated, the length and doping concentration of LDD is also optimized for better suppression of ambipolar current. Finally, analog/RF performance of HGD-LDD-LTFET are studied in terms of gate-source capacitance, gate-drain capacitance, cut-off frequency, and gain bandwidth production. TCAD simulation results show that HGD-LDD-LTFET not only drastically suppresses ambipolar current but also improves analog/RF performance compared with conventional LTFET. Highlights: In order to boost the on-current of Si-based TFET, the L-shaped TFET(LTFET) has been proposed. LTFET suffers from severe ambipolar behavior especially under low-Vg and high-Vd condition. Though several LTFET papers have been published, there is still a lack of investigation into ambipolar effect of LTFET. To reduce the ambipolar current, lightly doped drain (LDD) and hetero-gate-dielectric (HGD) are introduced into LTFET. Proposed LTFET with HGD and LDD not only reduces ambipolar current but also improves radio frequency performance .