Sol-gel solution-deposited InGaZnO thin film transistors

Area of Science:

• Materials Science
• Electronics Engineering
• Semiconductor Physics

Background:

• Thin film transistors (TFTs) are crucial components in electronic displays and circuits.
• Solution processing offers a cost-effective fabrication method for oxide semiconductors.
• Indium-Gallium-Zinc oxide (IGZO) is a promising material for high-performance TFTs.

Purpose of the Study:

• To investigate the performance of sol-gel derived In-Ga-Zn oxide TFTs.
• To correlate TFT properties with precursor chemistry and processing variables.
• To understand the impact of mobility on device stability under bias stress.

Main Methods:

• Fabrication of TFTs using sol-gel processing of In-Ga-Zn oxide precursors.
• Characterization of TFT electrical properties, including mobility and threshold voltage.
• Evaluation of device stability under positive dark bias stress and negative bias illumination stress.

Main Results:

• TFT mobility varied widely, with peak values of ~30 cm²/Vs for IZO and ~20 cm²/Vs for IGZO.
• High mobility TFTs demonstrated significantly reduced positive dark bias stress effects, indicating enhanced stability.
• Negative bias illumination stress effects were also weaker in higher mobility devices, with distinct characteristic properties observed.

Conclusions:

• The chemistry and thermodynamics of the sol-gel process influence self-compensated donor and acceptor states.
• These states dictate TFT mobility, threshold voltage, and bias stress behavior.
• High mobility in IGZO TFTs fabricated via sol-gel processing leads to superior operational stability.