標題: | Positive gate bias instability alleviated by self-passivation effect in amorphous InGaZnO thin-film transistors |
作者: | Li, GongTan Yang, Bo-Ru Liu, Chuan Lee, Chia-Yu Tseng, Chih-Yuan Lo, Chang-Cheng Lien, Alan Deng, ShaoZhi Shieh, Han-Ping D. Xu, NingSheng 光電工程學系 顯示科技研究所 Department of Photonics Institute of Display |
關鍵字: | InGaZnO;reliability;self-passivation;thin-film transistor;positive gate bias stress |
公開日期: | 2-十二月-2015 |
摘要: | The threshold voltage shift (Delta Vth) under positive gate bias stress (PGBS), generally found in amorphous InGaZnO thin-film transistors (a-IGZO TFTs), has usually been suppressed by external passivation layers. We report it can also be alleviated by the self-passivation effect of the active layer, where moderately increasing the active layer thickness (d(s)) reduces Delta Vth by 82% in SiOx-passivated a-IGZO TFTs. Our experiments in conjunction with simulations show that the instability of V-th comes from ambient factors at the back channel. Larger d(s) results in lower carrier concentrations at the back channel (N-back), fewer diffusive ions affecting the front channel, and much more stable operations under PGBS. The optimal thickness of an IGZO film simultaneously obtaining a small Delta V-th, near-zero Vth, and sharp sub-threshold swing is about 80-90 nm, thicker than those usually adopted. The self-passivation effect combined with the externally deposited passivation layer can improve the overall device reliability. |
URI: | http://dx.doi.org/10.1088/0022-3727/48/47/475107 http://hdl.handle.net/11536/129541 |
ISSN: | 0022-3727 |
DOI: | 10.1088/0022-3727/48/47/475107 |
期刊: | JOURNAL OF PHYSICS D-APPLIED PHYSICS |
Volume: | 48 |
Issue: | 47 |
顯示於類別: | 期刊論文 |