Drain-Engineered TFET With Fully Suppressed Ambipolarity for High-Frequency Application

• Published in: IEEE transactions on electron devices Vol. 66; no. 4; pp. 1628 - 1634
• Main Authors: Uddin Shaikh, Mohd Rizwan, Loan, Sajad A
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-04-2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Ambipolar leakage; band-to-band tunneling (BTBT); Doping; Fabrication; Field effect transistors; Junctions; Leakage; Logic gates; Semiconductor devices; Silicon; T shape; TFETs; Transconductance; tunnel field-effect transistor (TFET); Tunneling; Vertical drains
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2019.2896674

In this paper, we propose and simulate a novel drain-engineered structure of a quadruple-gate tunnel field-effect transistor (TFET). The proposed device employs a lateral dual source with a vertical drain extension on top of T-shaped channel region. This enables the modification of screening length (<inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula>) by varying the silicon film (<inline-formula> <tex-math notation="LaTeX">{t}_{\textsf {Si},\textsf {v}} </tex-math></inline-formula>) and the oxide (<inline-formula> <tex-math notation="LaTeX">{t}_{\textsf {Si},\textsf {v}} </tex-math></inline-formula>) thicknesses at the channel-drain junction to overcome the limitations of high ambipolar leakage in the conventional double-gate TFET (DG-TFET). A 2-D calibrated simulation study has revealed the doubling of on-current (<inline-formula> <tex-math notation="LaTeX">{I}_{ \mathrm{\scriptscriptstyle ON}} </tex-math></inline-formula>) and significantly suppressed ambipolar leakage (<inline-formula> <tex-math notation="LaTeX">{I}_{\textsf {AMB}} </tex-math></inline-formula>) in the proposed device as compared to the conventional DG-TFET. Furthermore, a five orders of magnitude improvement in <inline-formula> <tex-math notation="LaTeX">{I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}} </tex-math></inline-formula>, 73% increase in transconductance (<inline-formula> <tex-math notation="LaTeX">{g}_{\textsf {m}} </tex-math></inline-formula>), 62% increase in cutoff frequency (<inline-formula> <tex-math notation="LaTeX">{f}_{\textsf {T}} </tex-math></inline-formula>), 72% increase in gain-bandwidth product, and 54% improvement in fall propagation delay (<inline-formula> <tex-math notation="LaTeX">{t}_{\textsf {pHL}} </tex-math></inline-formula>) are achieved in the proposed device.