Optimizing nucleation layers for the integration of ferroelectric HZO on CVD-grown graphene

TL;DR

This study explores how different nucleation layers, specifically Ta and Pt, affect the deposition and ferroelectric properties of HZO on graphene, aiming to optimize integration for electronic applications.

Contribution

It investigates the effects of Ta and Pt nucleation layers on HZO deposition and ferroelectric performance on graphene, providing insights for improved integration strategies.

Findings

Ta leads to unstable switching at thicker layers

Oxidized Ta can achieve higher polarization at smaller thicknesses

Pt offers higher endurance in ferroelectric switching

Abstract

Direct integration of ferroelectric Hf0.5Zr0.5O2 (HZO) on the inert surface of graphene is challenging. Here, using nucleation layers to promote atomic layer deposition of HZO was investigated. Different metals were deposited as nucleation layers via dc sputtering. Ta, which oxidizes in air to form a sub-stoichiometric oxide, was compared to Pt, which offers a more stable electrode. For thicker interlayers, Ta leads to unstable switching behavior of the HZO film. Conversely, at smaller thicknesses, a higher Pr can be achieved with an oxidized Ta interlayer. In both cases, Pt offers higher endurance. The choice of interlayer may strongly depend on the required application.