Sulfur redox mediator for low-temperature flexible amorphous oxide CMOS electronics

Area of Science:

• Materials Science
• Semiconductor Physics
• Electronics Engineering

Background:

• Amorphous p-type oxides are critical for advanced flexible and scalable complementary metal-oxide semiconductor (CMOS) technologies.
• Tellurium-based oxides (Te-TeO_x) offer potential due to embedded Te-Te conduction networks but face challenges in controlled formation for optimal hole transport and dopability at low thermal budgets.

Purpose of the Study:

• To develop a method for controlled formation of Te-Te conduction channels in amorphous tellurium-based oxides.
• To enable high-performance p-channel thin-film transistors (TFTs) processed at ultralow temperatures.

Main Methods:

• A sulfur-mediated redox strategy was employed to modulate the local bonding environment.
• This involved TeO₂ dissociation and partial Te⁴⁺ reduction to promote short-chain Te-Te network formation.

Main Results:

• High-performance p-channel TFTs were fabricated with an average hole mobility of 11.5 cm² V^-1 s^-1 and on/off ratios of ~10⁶.
• The process was achieved at an ultralow temperature of 120°C with high uniformity and reproducibility.
• Integrated all-oxide CMOS circuits, including inverters and ring oscillators, demonstrated successful functionality on flexible and rigid substrates.

Conclusions:

• The sulfur-mediated strategy effectively promotes the formation of Te-Te conduction networks, enabling ultralow-temperature processing of high-performance amorphous p-type oxides.
• This approach paves the way for next-generation flexible and scalable electronic devices and circuits.