Tailoring Lattice Strain and Ferroelectric Polarization of Epitaxial BaTiO3 Thin Films on Si(001)

TL;DR

This paper demonstrates how to control ferroelectric polarization in BaTiO3 thin films on Si(001) by adjusting deposition temperature, affecting strain and polarization without relying solely on substrate choice.

Contribution

It introduces a novel method to tailor ferroelectric polarization through deposition temperature, overcoming limitations of traditional strain engineering.

Findings

Strain exceeding 2% achieved in films over 100 nm thick.

Deposition temperature critically influences film strain and polarization.

Epitaxial films with high polarization are successfully integrated on Si(001).

Abstract

Ferroelectric BaTiO3 films with large polarization have been integrated with Si(001) by pulsed laser deposition. High quality c-oriented epitaxial films are obtained in a substrate temperature range of about 300 deg C wide. The deposition temperature critically affects the growth kinetics and thermodynamics balance, resulting on a high impact in the strain of the BaTiO3 polar axis, which can exceed 2% in films thicker than 100 nm. The ferroelectric polarization scales with the strain and therefore deposition temperature can be used as an efficient tool to tailor ferroelectric polarization. The developed strategy overcomes the main limitations of the conventional strain engineering methodologies based on substrate selection: it can be applied to films on specific substrates including Si(001) and perovskites, and it is not restricted to ultrathin films.