A Silicon Nanocrystal Tunnel Field Effect Transistor

TL;DR

This paper introduces a silicon nanocrystal FET that leverages tunneling in undoped silicon structures, achieving high on/off ratios and low leakage, with potential for scalable, atomic-level device integration.

Contribution

It demonstrates a novel undoped silicon nanocrystal FET with tunneling operation, high symmetry, and improved scalability over traditional doped TFETs.

Findings

10^4 on/off current ratio at room temperature

Leakage current of 30 pA/μm at 0.5 V bias

Bipolar operation with high symmetry

Abstract

In this work, we demonstrate a silicon nanocrystal Field Effect Transistor (ncFET). Its operation is similar to that of a Tunnelling Field Effect Transistor (TFET) with two barriers in series. The tunnelling barriers are fabricated in very thin silicon dioxyde and the channel in intrinsic polycrystalline silicon. The absence of doping eliminates the problem of achieving sharp doping profiles at the junctions, which has proven a challenge for large-scale integration and in principle allows scaling down the atomic level. The demonstrated ncFET features a 10$^4$ on/off current ratio at room temperature, a low 30 pA/$\mu$m leakage current at a 0.5 V bias, an on-state current on a par with typical all-Si TFETs and bipolar operation with high symmetry. Quantum dot transport spectroscopy is used to assess the band structure and energy levels of the silicon island.