Doping Nitrogen in InGaZnO Thin Film Transistor with Double Layer Channel Structure

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Amorphous Indium Gallium Zinc Oxide (IGZO) is a promising material for thin film transistors (TFTs).
• Optimizing doping strategies is crucial for enhancing IGZO TFT performance and stability.
• Nitrogen doping presents a novel approach to modify the electrical properties of IGZO.

Purpose of the Study:

• To investigate the electrical characteristics of amorphous IGZO thin film transistors doped with nitrogen.
• To evaluate the impact of nitrogen doping on the performance and stability of IGZO TFTs.
• To compare the performance of nitrogen-doped IGZO (IGZO:N) with oxygen-doped IGZO.

Main Methods:

• Amorphous IGZO:N films were deposited using radio frequency (RF) sputtering with a nitrogen and argon gas mixture at room temperature.
• Electrical characteristics including threshold voltage, field-effect mobility, on/off current ratio, and subthreshold swing were measured.
• Positive gate bias stress stability was assessed to evaluate device reliability.

Main Results:

• The optimized IGZO:N/IGZO TFT exhibited a threshold voltage of 0.5 V and a field-effect mobility of 14.34 cm2V-1S-1.
• An on/off current ratio of 10^6 and a subthreshold swing of 1.48 V/decade were achieved.
• Nitrogen doping significantly improved the positive gate bias stress stability compared to oxygen doping.

Conclusions:

• Nitrogen doping is an effective method for enhancing the electrical performance of amorphous IGZO TFTs.
• IGZO:N TFTs demonstrate superior stability under positive gate bias stress, indicating improved reliability.
• This study highlights the potential of nitrogen doping for developing advanced IGZO-based electronic devices.