Reversible Thickness Engineering in Amorphous In₂O₃ Transistors

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Amorphous oxide semiconductors offer advantages in device processing due to their noncrystalline nature.
• This enables low-temperature processing and eliminates lattice-matching requirements at interfaces.

Purpose of the Study:

• To demonstrate atomic-scale, reversible thickness control of amorphous indium oxide (In2O3) films.
• To leverage chemical continuity for precise film modulation.
• To establish film thickness as a key design parameter for oxide semiconductors.

Main Methods:

• Integration of bottom-up atomic layer deposition with top-down hydroxide-assisted wet-etching.
• Bidirectional modulation of In2O3 film thickness between 1 and 4 nm.
• Maintaining smooth surfaces (Ra ≈ 0.5 nm) and stable chemical composition.

Main Results:

• Achieved reversible, atomic-scale thickness control of amorphous In2O3 films.
• Demonstrated thickness-dependent control over In2O3 transistor performance.
• Enabled doping-free modulation of threshold voltage and reversible switching between depletion and enhancement modes.
• Successfully demonstrated inverters and ring oscillators.

Conclusions:

• The thinning-regrowth process offers precise control over amorphous oxide semiconductor properties.
• Film thickness is established as a critical design parameter for oxide semiconductors.
• This technique paves the way for developing reconfigurable electronic devices.