51. Electrical stress-induced instability of amorphous indium-gallium-zinc oxide thin-film transistors under bipolar ac stress
- Author
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Ji-Hyun Hur, Sungchul Kim, Dae Hwan Kim, U-In Jung, I-hun Song, Kichan Jeon, Sang-Wook Kim, Dongsik Kong, Jun-Hyun Park, Chang Jung Kim, Youngsoo Park, Sunil Kim, Sangwon Lee, Jae Chul Park, and Dong Myong Kim
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Thin-film transistor ,Gate dielectric ,Density of states ,Optoelectronics ,Dielectric ,Sputter deposition ,business ,Subthreshold slope ,Threshold voltage ,Amorphous solid - Abstract
Bipolar ac stress-induced instability of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors is comparatively investigated with that under a positive dc gate bias stress. While the positive dc gate bias stress-induced threshold voltage shift (ΔVT) is caused by the charge trapping into the interface/gate dielectric as reported in previous works, the dominant mechanism of the ac stress-induced ΔVT is observed to be due to the increase in the acceptorlike deep states of the density of states (DOS) in the a-IGZO active layer. Furthermore, it is found that the variation of deep states in the DOS makes a parallel shift in the IDS-VGS curve with an insignificant change in the subthreshold slope, as well as the deformation of the CG-VG curves.
- Published
- 2009