Vertical Tunnel FET: Design Optimization With Triple Metal-Gate Layers

• Published in: IEEE transactions on electron devices Vol. 63; no. 12; pp. 5030 - 5035
• Main Authors: Ko, Eunah, Lee, Hyunjae, Park, Jung-Dong, Shin, Changhwan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-12-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Ambipolar current regulation; CAD; Computer aided design; Design optimization; Field effect transistors; gate-length engineering; Parameters; Performance evaluation; Semiconductor device modeling; Semiconductor devices; TFETs; triple metal-gate (TMG) tunnel FET (TFET); Tunneling; Tunnels; vertical TFET; Work functions; work-function engineering
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2016.2619372

The effect of a triple metal-gate (TMG) on the performance and on the ambipolar current in a TMG vertical tunnel field-effect transistor with triple metal-gate (TMG-TFET) is investigated using technology computer-aided design simulation. The TMG-TFET is designed to tackle the performance as well as the ambipolar current, simultaneously, by modulating the TMG parameters-the work function of the TMG and/or the length of each MG-that have critical impacts on the energyband diagrams of the channel region. The tempered on-/offcurrent ratio of 10 8 and the steep average subthreshold slope of 43.5 mV/decade at a power supply voltage of 0.5 V are ascribed to the formation of an energy barrier in the channel by the optimal device parameters. It is found that two main flaws in a conventional (single-material gate) TFET, which are the degraded on-state current and the ambipolar current, can be successfully controlled by adjusting the TMG structure.