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-Dec-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
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