Performance enhancement of ATZO TFTs by component control and post treatment

Al-Sn-Zn-O (ATZO) was developed as an In-free oxide semiconductor for thin film transistors (TFTs) channel layer. In this paper we fabricated ATZO TFTs and optimized the electrical performance by adjusting the concentration of Al and Sn in ATZO, post annealing and plasma treatment. It was found that higher Al and Sn concentration leads to lower grain size and higher TFT on/off ratio, and post annealing in air helps to enhance the mobility of ATZO TFTs. N
₂
O plasma treatment significantly suppress the off current without a degradation of mobility. By combining aforementioned methods, ATZO TFTs with Ion/I
_off
of 5.77×10
⁷
, and subthreshold swing (SS) of 0.205 V/dec was achieved, which shows potential for flat panel display applications.