Probing Hf0.5Zr0.5O2 Ferroelectricity: Neutron Reflectivity Reveals Critical Interface Effects
Journal
ACS Applied Materials & Interfaces
Journal Volume
17
Journal Issue
10
Start Page
16102
End Page
16110
ISSN
1944-8244
1944-8252
Date Issued
2025-03-12
Author(s)
Abstract
Ferroelectric Hf0.5Zr0.5O2 (HZO) thin films emerge as promising candidates for next-generation memory devices; however, the device performance is strongly correlated to the interfacial structure. In this study, neutron reflectivity was used for the first time to conduct an in-depth analysis of the ferroelectric W/HZO/W devices, leveraging the high sensitivity of neutron scattering length density (SLD) to the buried interfaces. We explored the impact of different atomic layer deposition (ALD) techniques─thermal, plasma, and atomic layer annealing (ALA)─on the structural and ferroelectric characteristics of HZO thin films, with a particular focus on interfacial structures. Analyses using neutron reflectivity, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy revealed the critical role of the bottom WOx interfacial layer. The ALA treatment contributes to significant enhancements in structural and ferroelectric properties, including an increase in film density and crystallinity, as well as a maximum neutron SLD due to reduced oxygen vacancies. This work elucidates the crucial role of interface engineering via interfacial layer formation in stabilizing the ferroelectric phase, providing valuable insights for the development of advanced ferroelectric devices.
Subjects
ferroelectric
Hf0.5Zr0.5O2 (HZO)
interface
neutron reflection
tungsten oxide
Publisher
American Chemical Society (ACS)
Type
journal article