Implementation of High‐Performance Solution‐Processed Amorphous Indium–Gallium–Zinc–Oxide Thin‐Film Transistors with Low Charge Traps by Microwave Heat Treatment of Low Thermal Budget

Abstract

Herein, high‐performance solution‐processed amorphous indium–gallium–zinc–oxide (a‐IGZO) thin‐film transistors (TFTs) with low trap densities due to post‐deposition annealing (PDA) are processed with a low‐thermal‐budget microwave (MW) heat treatment. To verify the MW effectiveness, the composition ratio of a‐IGZO thin films and the electrical characteristics of TFTs prepared by conventional thermal annealing (CTA) are compared. An X‐ray photoelectron spectroscopy (XPS) analysis reveals that MW annealing (MWA) improves the film quality more effectively than CTA. a‐IGZO TFTs treated by MWA or CTA are fabricated to evaluate their electrical characteristics. MWA is more effective than CTA in improving the performance, such as hysteresis, subthreshold swing (SS), field effect mobility (μ FE), and on/off current ratio (I on/I off). MWA provides lower interfacial trap density (D it) and volume trap density (N t) than CTA. To evaluate instability, the threshold voltage (V TH) shift is monitored using positive and negative gate‐bias stress tests. MWA demonstrates better reliability than CTA. In conclusion, high‐performance solution‐based a‐IGZO TFTs can be implemented by lowering the charge traps in the a‐IGZO channel using MWA.