Crystallinity-Preserving Atomic Layer Etching of Ultrathin In₂O₃ for Stable Oxide Nanoelectronics

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Indium oxide (In2O3) is a key material for advanced electronics due to its high electron mobility and wide bandgap.
• Conventional atomic layer deposition (ALD) methods struggle to produce ultrathin, crystalline In2O3 films with good grain connectivity.

Purpose of the Study:

• To develop a novel atomic layer etching (ALE) approach for fabricating high-quality ultrathin indium oxide films.
• To overcome the limitations of conventional ALD in achieving crystalline In2O3 layers.

Main Methods:

• A novel ALE method combining hydrogen-plasma-assisted surface modification and acetylacetone-assisted ligand removal was developed.
• An ALD/ALE etch-back process was employed to create ultrathin In2O3 films.

Main Results:

• In2O3 films as thin as 3 nm were successfully fabricated, maintaining a preferred (222) crystallographic orientation.
• The root-mean-square roughness of the films was reduced from 0.27 nm to 0.17 nm.
• The process preserved crystallographic order and surface morphology in ultrathin films, improving device performance.

Conclusions:

• The developed ALE process is a viable route for scalable fabrication of high-quality crystalline oxide semiconductors.
• This method enables the production of ultrathin In2O3 films crucial for next-generation nanoelectronics.