First Principle-based Analysis of Single-Walled Carbon Nanotube and Silicon Nanowire Junctionless Transistors

TL;DR

This paper analyzes the potential of junctionless transistors using doped carbon nanotubes compared to silicon nanowires, highlighting differences in electrical performance and material properties.

Contribution

It introduces a first-principles analysis of CNT-based junctionless transistors, comparing their electrical characteristics with silicon nanowire devices.

Findings

CNT transistors have higher on-current than silicon nanowires.

Device performance is limited by the smaller band gap of CNTs.

Silicon nanowire devices exhibit better overall characteristics.

Abstract

Junctionless transistors made of silicon have previously been demonstrated experimentally and by simulations. Junctionless devices do not require fabricating an abrupt source-drain junction and thus can be easier to implement in aggressive geometries. In this paper, we explore a similar architecture for aggressively scaled devices with the channel consisting of doped carbon nanotubes (CNTs). Gate all around (GAA) field effect transistor (FET) structures are investigated for n- and p-type doping. Current-voltage characteristics and sub-threshold characteristics for a CNTbased junctionless FET is compared with a junctionless silicon nanowire (SiNW) FET with comparable dimensions. Despite the higher on-current of the CNT channels, the device characteristics are poorer compared to the silicon devices due to the smaller CNT band gap.