In-Grain Ferroelectric Switching in Sub-5 nm Thin Al_0.74 Sc_0.26 N Films at 1 V

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Ferroelectric devices offer high energy efficiency for neuromorphic computing.
• Device scalability is a key challenge for realizing efficient neuromorphic applications.
• Wurtzite-type ferroelectrics are promising candidates for advanced electronic devices.

Purpose of the Study:

• To investigate the ferroelectric switching characteristics of sub-5 nm AlScN films.
• To overcome scalability limitations in ferroelectric devices for neuromorphic computing.
• To demonstrate the potential of AlScN for energy-efficient analog switching.

Main Methods:

• Sputter-deposition of sub-5 nm Al0.74Sc0.26N films on Pt/Ti/SiO2/Si and epitaxial Pt/GaN/sapphire templates.
• Characterization of ferroelectric switching voltages and coercive field.
• Atomic-scale imaging using scanning transmission electron microscopy (STEM).

Main Results:

• Achieved record low switching voltages down to 1V, compatible with on-chip sources.
• Observed a significantly larger coercive field to breakdown field ratio in Al0.74Sc0.26N films on silicon substrates.
• Demonstrated the formation of ferroelectric domains and inversion domain boundaries (IDBs) at the atomic scale in sub-5 nm films.

Conclusions:

• Sub-5 nm AlScN films exhibit promising ferroelectric properties for neuromorphic computing.
• The observed switching characteristics and domain structures support a gradual domain-wall driven switching mechanism.
• These findings enable analog switching in highly scaled ferroelectric devices for neuromorphic applications.