Inverters with Different Load Configurations and a Two-Input Multiplexer Based on IGZO NMOS TFTs.

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) are key for advanced electronics due to high mobility and low power consumption.
• Their compatibility with low-temperature processing on flexible substrates makes them ideal for next-generation applications.

Purpose of the Study:

• To fabricate and characterize bottom-gate a-IGZO NMOS TFTs with HfO2 dielectric and Mo contacts.
• To design, fabricate, and compare inverters with various load configurations (resistive, diode, depletion, pseudo-CMOS).
• To evaluate a-IGZO TFT-based multiplexer performance for digital and mixed-signal circuits.

Main Methods:

• Fabrication of bottom-gate a-IGZO NMOS TFTs.
• Electrical characterization using capacitance-voltage (C-V) and current-voltage (I-V) measurements.
• Design and characterization of a-IGZO TFT-based inverters and a two-channel multiplexer.

Main Results:

• Extracted key device parameters from C-V and I-V measurements.
• Identified depletion-load inverters as exhibiting the highest gain and noise margins.
• Demonstrated successful operation of a two-channel multiplexer with robust switching behavior up to 1 kHz.

Conclusions:

• a-IGZO TFTs are suitable for low-power, high-reliability digital and mixed-signal electronics.
• Depletion-load inverter configuration offers optimal performance for a-IGZO TFT circuits.
• The fabricated multiplexer confirms the potential of a-IGZO TFTs in integrated circuits.