Abnormal positive bias stress instability of In-Ga-Zn-O thin-film transistors with low-temperature Al2O3 gate dielectric

Yu Hong Chang, Ming Jiue Yu, Ruei Ping Lin, Chih Pin Hsu, Tuo-Hung Hou*

*此作品的通信作者

研究成果: Article同行評審

47 引文 斯高帕斯(Scopus)

摘要

Low-temperature atomic layer deposition (ALD) was employed to deposit Al2O3 as a gate dielectric in amorphous In-Ga-Zn-O thin-film transistors fabricated at temperatures below 120 °C. The devices exhibited a negligible threshold voltage shift (ΔVT) during negative bias stress, but a more pronounced ΔVT under positive bias stress with a characteristic turnaround behavior from a positive ΔVT to a negative ΔVT. This abnormal positive bias instability is explained using a two-process model, including both electron trapping and hydrogen release and migration. Electron trapping induces the initial positive ΔVT, which can be fitted using the stretched exponential function. The breakage of residual AlO-H bonds in low-temperature ALD Al2O3 is triggered by the energetic channel electrons. The hydrogen atoms then diffuse toward the In-Ga-Zn-O channel and induce the negative ΔVT through electron doping with power-law time dependence. A rapid partial recovery of the negative ΔVT after stress is also observed during relaxation.

原文English
文章編號033502
頁數4
期刊Applied Physics Letters
108
發行號3
DOIs
出版狀態Published - 18 1月 2016

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