Room-Temperature Radical-Complexation Wet Etch Chemistry Demonstrated on VO2

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Metal oxide device fabrication faces challenges with pattern fidelity and low thermal budgets.
• Existing etching strategies for vanadium dioxide (VO2) thin films are limited.

Purpose of the Study:

• To develop a room-temperature wet etching strategy for VO2 thin films.
• To improve pattern fidelity, material preservation, and device reproducibility in oxide electronics.

Main Methods:

• A novel HCl/H2O2 wet etching system was developed for VO2 thin films.
• The system utilizes radical-assisted oxidation and chloride complexation for efficient material removal.
• Characterization included structural, morphological, electrical, and device-level analyses.

Main Results:

• The HCl/H2O2 system achieved a high VO2 etch rate (5.64 nm/min) and excellent selectivity (806:1) over sapphire substrates.
• Minimized lateral width loss (0.47 µm) was observed, with increased selectivity and reduced lateral loss compared to conventional etchants.
• Etching preserved intrinsic VO2 properties and reduced device switching variability by up to 38%.

Conclusions:

• The developed wet etching strategy offers a practical framework for reliable fabrication of functional oxide devices.
• Mechanism-driven wet chemistry can simultaneously enhance pattern fidelity, material preservation, and device reproducibility.
• This approach establishes a direct process-structure-device relationship crucial for oxide electronics advancement.