Influence of metallization process on solution-processed InGaZnO thin film transistors

Area of Science:

• Materials Science
• Electronics Engineering
• Semiconductor Physics

Background:

• Low-temperature solution-processed Indium Gallium Zinc Oxide (IGZO) thin-film transistors (TFTs) are key for next-generation flexible displays due to transparency, performance, and scalability.
• Challenges remain in improving film quality and stability for amorphous IGZO TFTs.

Purpose of the Study:

• To systematically investigate the impact of the metallization process on the characteristics of solution-processed amorphous IGZO TFTs.
• To optimize device performance through post-annealing and passivation techniques.

Main Methods:

• Fabrication of IGZO TFTs with aluminum (Al) source and drain electrodes.
• Electrical characterization including threshold voltage (Vth) and subthreshold swing (SS) measurements.
• Spectroscopic analysis to understand material composition and interface effects.

Main Results:

• Aluminum electrodes induce a doping effect and oxygen vacancy-related oxidation, causing a negative shift in Vth.
• Low-temperature post-annealing and polymer passivation successfully shifted Vth from >150 V to near 0 V.
• Significant improvements in subthreshold swing (SS) were achieved.

Conclusions:

• Source-drain metallization critically influences IGZO TFT device characteristics through the interplay of metal oxidation and oxygen vacancies.
• Optimized post-processing steps are essential for enhancing the stability and electrical performance of solution-processed IGZO TFTs.