A grease for domain walls motion in HfO₂-based ferroelectrics.

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• High coercive fields (Ec) in hafnium oxide (HfO2)-based ferroelectric devices limit their use in memory and transistor applications.
• Reducing Ec is crucial for enhancing the performance and reliability of ferroelectric devices.

Purpose of the Study:

• To develop a new HfO2-based ferroelectric material with a reduced coercive field (Ec).
• To investigate the impact of nanolaminate structures on the polarization reversal dynamics and dielectric properties.

Main Methods:

• Fabrication of nanolaminate Hf0.5Zr0.5O2/ZrO2 (HZZ) thin films.
• Annealing HZZ films at 700 °C.
• High-resolution electron microscopy for structural analysis.
• Capacitance-voltage (C-V) measurements to assess dielectric properties.

Main Results:

• The HZZ thin films exhibited tetragonal-like domain walls between orthorhombic polar regions.
• A significant reduction of approximately 40% in the coercive field (Ec) was observed compared to conventional HfO2 films.
• HZZ films showed increased dielectric permittivity near Ec, indicating enhanced domain wall mobility.

Conclusions:

• The nanolaminate HZZ structure effectively reduces the coercive field (Ec) by facilitating domain wall motion.
• Tetragonal-like domain walls act as a lubricant, lowering the energy barrier for polarization reversal.
• This approach offers a promising pathway for developing high-performance ferroelectric memories and transistors.