Effect of High-k Dielectric Layer on 1/f Noise Behavior in Graphene Field-Effect Transistors

TL;DR

This study investigates how a high-k dielectric layer affects low-frequency 1/f noise in graphene transistors, revealing insights into noise mechanisms and ways to reduce it for improved device performance.

Contribution

It demonstrates the impact of a tantalum oxide high-k dielectric layer on 1/f noise behavior in graphene FETs and explains the physical noise origins.

Findings

Achieved low 1/f noise level of ~2.2 x 10^(-10) Hz^(-1) at 10 Hz.

Identified carrier number fluctuations as the dominant noise source.

Optimized fabrication reduces charged impurities and noise.

Abstract

We report the 1/f noise characteristics at low-frequency in graphene field-effect transistors that utilized a high-k dielectric tantalum oxide encapsulated layer (a few nanometers thick) placed by atomic layer deposition on Si3N4. A low-noise level of ~ 2.2 x 10^(-10) Hz-1 has been obtained at f = 10 Hz. The origin and physical mechanism of the noise can be interpreted by the McWhorter context, where fluctuations in the carrier number contribute dominantly to the low-frequency noise. Optimizing fabrication processes reduced the number of charged impurities in the graphene field-effect transistors. The study has provided insights into the underlying physical mechanisms of the noise at low-frequency for reducing the noise in graphene-based devices.