Probing Hf_0.5Zr_0.5O₂ Ferroelectricity: Neutron Reflectivity Reveals Critical Interface Effects.

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Ferroelectric hafnium zirconium oxide (HZO) thin films are crucial for advanced memory devices.
• Device performance in HZO-based memory is highly dependent on the structure of buried interfaces.

Purpose of the Study:

• To investigate the impact of different atomic layer deposition (ALD) techniques on HZO thin films.
• To analyze the interfacial structures and their correlation with ferroelectric properties using neutron reflectivity.
• To elucidate the role of interface engineering in stabilizing the ferroelectric phase.

Main Methods:

• Neutron reflectivity (NR) for in-depth analysis of buried W/HZO/W interfaces.
• High-resolution transmission electron microscopy (HRTEM).
• X-ray photoelectron spectroscopy (XPS).

Main Results:

• Neutron reflectivity revealed the critical role of the bottom tungsten oxide (WOx) interfacial layer.
• Atomic layer annealing (ALA) treatment significantly enhanced HZO film density and crystallinity.
• ALA treatment led to reduced oxygen vacancies and a maximum neutron scattering length density (SLD).

Conclusions:

• Interface engineering, specifically the formation of an interfacial layer, is crucial for stabilizing the ferroelectric phase in HZO.
• ALA treatment offers a promising approach for optimizing HZO thin films for next-generation memory devices.
• This study provides valuable insights into the structure-property relationships for advanced ferroelectric memory applications.