Phase-Composite InO Semiconductors for High-Performance Flexible Thin-Film Transistors

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Indium oxide (InO) is a promising material for thin-film transistors (TFTs) due to its high electron mobility and optical transparency.
• However, its application is hindered by high carrier concentration, poor crystallization control, and instability.
• Developing advanced fabrication methods is crucial for overcoming these limitations.

Purpose of the Study:

• To fabricate amorphous/nanocrystal phase-composite indium oxide (InO) films using high-pressure atomic layer deposition (ALD).
• To investigate the effect of deposition temperature and channel thickness on film properties and device performance.
• To address limitations in carrier concentration, phase control, and mechanical durability for next-generation TFTs.

Main Methods:

• Fabrication of InO films via high-pressure atomic layer deposition (ALD) using InCA-1 precursor and H2O2 oxidant.
• Systematic variation of deposition temperature and channel thickness to control film structure and carrier concentration.
• Characterization of film properties, including electrical performance, optical transmittance, surface morphology, mechanical flexibility, and environmental stability.

Main Results:

• Achieved amorphous/nanocrystal phase-composite InO films with controlled carrier concentration and enhanced electron transport via resonant hybridization.
• Optimized films (110 °C, 7.0 nm thick) demonstrated high field-effect mobility (61.1 cm2 V-1 s-1), on/off ratio (0.9 × 10^6), and low subthreshold swing (0.45 V dec-1).
• Exhibited excellent reproducibility, optical transmittance (>87%), mechanical flexibility (10,000 bending cycles), and environmental stability (60 days).

Conclusions:

• The developed phase-composite InO films overcome critical limitations of conventional InO-based TFTs.
• ALD enables precise control over phase composition, carrier concentration, and film thickness.
• These findings pave the way for advanced, durable, and high-performance electronic and optoelectronic devices.