Transparent Electronics Using One Binary Oxide for All Transistor Layers

Area of Science:

• Materials Science
• Electronics Engineering
• Nanotechnology

Background:

• Traditional thin-film transistors (TFTs) often require multiple deposition steps and high temperatures.
• Indium-based oxides are common in transparent electronics but face cost and availability challenges.
• Developing alternative materials and processes for high-performance, low-cost transparent electronics is crucial.

Purpose of the Study:

• To develop a novel, low-temperature fabrication process for TFTs using a single binary oxide.
• To tune the electronic properties of hafnium-zirconium-oxide (HZO) for various transistor layers.
• To demonstrate the performance of all-HZO TFTs and integrated circuits on flexible substrates.

Main Methods:

• Fabrication of all-HZO TFTs in a single atomic layer deposition system at low temperatures.
• Tuning HZO electronic properties (conducting, semiconducting, insulating) by adjusting precursor flow ratios.
• Optimization of HZO layers for gate, source/drain, channel, and dielectric functions.

Main Results:

• Achieved excellent TFT performance: saturation mobility of ≈17.9 cm²/V·s, subthreshold swing of ≈480 mV/dec, and I_on/I_off ratio >10⁹.
• Demonstrated superior gate bias stability at elevated temperatures.
• Fabricated all-HZO inverters with high DC voltage gain (≈470) and ring oscillators with low stage delay (≈408 ns).

Conclusions:

• A novel, simple, and cost-effective process for fabricating high-performance all-HZO TFTs is presented.
• This approach enables indium-free transparent electronics on both glass and plastic substrates.
• The demonstrated performance of TFTs, inverters, and ring oscillators highlights the potential for advanced electronic applications.