Title: Electrical and Photosensitive Characteristics of a-IGZO TFTs Related to Oxygen Vacancy
Authors: Yao, Jianke
Xu, Ningsheng
Deng, Shaozhi
Chen, Jun
She, Juncong
Shieh, Han-Ping David
Liu, Po-Tsun
Huang, Yi-Pai
Department of Photonics
Institute of Display
Keywords: Absorption;amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT);electrical and photosensitive characteristics;oxygen vacancies
Issue Date: 1-Apr-2011
Abstract: The electrical and photosensitive characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) related to the oxygen vacancies V(O) are discussed. With the filling of V(O) of ratio from 14 to 8, the electron density of the a-IGZO channel decreases from 7.5 to 3.8 (x10(16) cm(-3)); the saturation mobility of the TFT decreases from 3.1 to 1.4 cm(2)/(V . s); the threshold voltage increases from 7 to 11 V for the TFT with a lower on-current; and the subthreshold slope increases from 2.4 to 4.4 V/dec for the TFT with a higher interface defect density of 4.9 x 10(11) cm(-2), the worst electrical stability of Delta V(th) similar to 10 V, and a hysteresis-voltage decrease from 3.5 to 2 V. The photoreaction properties of a-IGZO TFTs are also sensitive to the oxygen-content-related absorption of the a-IGZO channel. With the lowest content of oxygen in the channel, the TFT has the largest photocurrent gain of 50 mu A (V(g) = 30 V; V(d) = 10 V) and decrease in V(th) (|Delta V(th)| similar to 5 V) at a high light intensity. The light-induced change of TFT characteristics is totally reversible with the time constant for recovery of about 2.5 h.
URI: http://dx.doi.org/10.1109/TED.2011.2105879
ISSN: 0018-9383
DOI: 10.1109/TED.2011.2105879
Volume: 58
Issue: 4
Begin Page: 1121
End Page: 1126
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