Influence of Phonon Scattering on the Performance of p-i-n Band-to-Band-Tunneling Transistors

TL;DR

This paper investigates how phonon scattering affects the performance of p-i-n band-to-band tunneling transistors made from carbon nanotubes, revealing temperature-dependent off-current behavior and potential for low subthreshold swings.

Contribution

It provides new insights into phonon scattering effects on CNT-based TFETs, especially on off-current and subthreshold swing at room temperature.

Findings

Off-current is limited by phonon absorption-assisted tunneling.

Subthreshold swings below 60mV/decade are achievable at room temperature.

Phonon scattering moderately affects on-current but significantly impacts off-current.

Abstract

Power dissipation has become a major obstacle in performance scaling of modern integrated circuits, and has spurred the search for devices operating at lower voltage swing. In this letter, we study p-i-n band-to-band tunneling field effect transistors (TFET) taking semiconducting carbon nanotubes as the channel material. The on-current of these devices is mainly limited by the tunneling barrier properties, and phonon scattering has only a moderate effect. We show, however, that the off-current is limited by phonon absorption assisted tunneling, and thus is strongly temperature-dependent. Subthreshold swings below the 60mV/decade conventional limit can be readily achieved even at room temperature. Interestingly, although subthreshold swing degrades due to the effects of phonon scattering, it remains low under practical biasing conditions.