Open AccessImproved charging phenomenon with a modified barrier structure for flexible displays fabricated on polyimide substrates
Author(s) -
Kim H.J.,
Park J.M.,
Byun C.W.,
Bak S.R.,
Jung Y.J.,
Han C.H.,
Yoo J.M.,
Kim S.K.,
Choi P.H.,
Lee J.H.,
Song J.K.,
Choi B.D.
Publication year - 2021
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/ell2.12239
Subject(s) - polyimide , materials science , thin film transistor , layer (electronics) , capacitance , capacitor , transistor , secondary ion mass spectrometry , optoelectronics , stress (linguistics) , active layer , ion , analytical chemistry (journal) , composite material , voltage , electrode , electrical engineering , chemistry , linguistics , philosophy , organic chemistry , chromatography , engineering
In a previous study, the authors investigated that abnormal V th behaviour could occur due to polyimide charging when a voltage was applied to the gate in thin film transistors fabricated on polyimide substrates. The authors propose a barrier structure that could prevent this charging effect when fabricating flexible thin film transistors on polyimide substrates. The barrier layer was changed to an SiOCH/SiO 2 double layer to reduce the influence of fluorine ions generated in PI by negative bias temperature stress. To confirm the effect of the SiOCH layer, Al/PI/SiO 2 /Al, Al/PI/SiOCH/SiO 2 /Al metal‐insulator‐metal capacitors were fabricated and electrical properties were measured. When bias stress was applied, changes in current and capacitance were observed only in the device with a single SiO 2 barrier layer. In addition, it was confirmed through secondary ion mass spectrometry measurements that the Si–CH 3 bonds in the SiOCH layer were replaced with Si–F bonds by the fluorine ions originating from PI. It was also verified that the abnormal behaviour of V th did not occur after negative bias temperature stress of the thin film transistor fabricated using an SiOCH/SiO 2 double layer.