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Influence of gate dielectric/channel interface engineering on the stability of amorphous indium gallium zinc oxide thin‐film transistors
Author(s) -
Cho Sung Haeng,
Ryu Min Ki,
Kim HeeOk,
Kwon OhSang,
Park EunSook,
Roh YongSuk,
Hwang ChiSun,
Park SangHee Ko
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431062
Subject(s) - thin film transistor , materials science , threshold voltage , gate dielectric , amorphous solid , dielectric , gate oxide , optoelectronics , sputtering , gallium , stress (linguistics) , substrate (aquarium) , transistor , thin film , layer (electronics) , composite material , metallurgy , electrical engineering , voltage , nanotechnology , chemistry , linguistics , philosophy , organic chemistry , oceanography , geology , engineering
We report the simultaneous improvements of the threshold voltage ( V th ) stabilities under the prolonged positive gate bias stress (PBS) and negative gate bias under illumination stress (NBIS) by employing the gate dielectric/channel interface engineering in the bottom‐gate, DC‐sputtered amorphous indium gallium zinc oxide (a‐IGZO) thin‐film transistors (TFT). In the interfacial region, a‐IGZO is grown under the low oxygen partial pressure ( P O 2) condition to minimize the damage from highly energetic oxygen anion bombardment into the substrate during sputtering. Meanwhile, highP O 2is employed during the bulk growth of active film to reduce the oxygen vacancy (V O ) related defects in a‐IGZO, which is known to be a main cause for the degradation of the electrical properties of TFT under NBIS. Owing to the lower damage of the gate dielectric by interface engineering during sputter deposition, the charge trapping or injection probability into the gate dielectric is diminished. Consequently, V th instabilities due to both the electron trapping under PBS and the trapping of positively charged species under NBIS are alleviated simultaneously.