Anomalous On-current and Subthreshold Swing Improvement Induced by Negative Bias-Stress at high temperature in amorphous InGaZnO Thin-Film Transistors
Shin-Ping Huang1*, Ting-Chang Chang2,4, Bo-Wei Chen1, Ann-Kuo Chu1, Terry Tai-Jui Wang3, Tsu-Chiang Chang3, Bo-Yuan Su3
1Department of photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
2Department of physics, National Sun Yat-sen University, Kaohsiung, Taiwan
3Display Technology Center, Industrial Technology Research Institute, Hsinchu, Taiwan
4Advanced Optoelectronics Technology Center, National Cheng Kung University, Tainan, Taiwan
* presenting author:Shin Ping Huang,
This letter investigates the effect of negative bias stress induced abnormal degradation in amorphous InGaZnO thin-film transistors (TFTs) at high temperature. Drain current-gate voltage (ID-VG) and capacitance-voltage (C-V) measurements are employed to analyze degradation mechanism. High temperature negative bias stress lead to not only a negative parallel shift in ID-VG but also a C-V distortion at off-state. This attributes to a barrier lowering effect nearby both drain and source sides according to symmetrical hole-trapping effect. Furthermore, both on-current and subthreshold swing will be improved because of the reduction of effective length and screening effect induced by weak inversion in channel.

Keywords: Amorphous InGaZnO thin-film transistors, Negative Bias stress