Performance and Stability Enhancement of Fully Solution-Processed a-InZnO Thin-Film Transistors via Argon Plasma Treatment

The market is now moving to next-generation flexible electronics which requires the integration of functional solution-processed materials using simple and low-temperature fabrication techniques that are compatible with heat-sensitive substrates. Although several studies have reported on the high-performance solution-processed layer in oxide thin-film transistors (TFTs), achieving high mobility while maintaining good stability under the bias stress test remains a challenge. In this report, we show that argon (Ar) plasma treatment is an effective method for achieving fully solution-processed amorphous indium zinc oxide (a-IZO) TFTs with high stability and performance. Particularly, Ar plasma treatment can activate the electrode and induce TFT switching. The electrical performance of the a-IZO TFT was also enhanced by the Ar plasma treatment. From the experimental results, fully solution-processed a-IZO TFTs with high mobility up to 31.12 cm(2)/(V s) was achieved by Ar plasma treatment for 5 s at an Ar flow rate of 75 sccm. The stability behavior of the self-aligned top gate top contact a-IZO TFT treated with argon plasma was investigated under positive bias stress (PBS) and negative bias stress (NBS) with a smallest threshold voltage shift (Delta V-th) of -0.3 and 0.7 V for PBS and NBS, respectively. Delta V-th is improved due to the higher film densification which confirms better film quality. Higher mobile carrier with lower interface trap density and film densification are the main reasons behind the performance and stability improvement of these TFTs. These results show that the performance and stability enhancement of the fully solution-processed a-IZO TFT by plasma treatment has a large potential for future low-temperature flexible device applications.