title: Effect of the electrode materials on the drain-bias stress instabilities of In-Ga-Zn-O thin-film transistors.
abstract: The effects of electrode materials on the device stabilities of In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) were investigated under gate- and/or drain-bias stress conditions. The fabricated IGZO TFTs with a top-gate bottom-contact structure exhibited very similar transfer characteristics between the devices using indium-tin oxide (ITO) and titanium electrodes. Typical values of the mobility and threshold voltage of each device were obtained as 13.4 cm(2) V(-1) s(-1) and 0.72 V (ITO device) and 13.8 cm(2) V(-1) s(-1) and 0.66 V (titanium device). Even though the stabilities examined under negative and positive gate-bias stresses showed no degradation for both devices, the instabilities caused by the drain-bias stress were significantly dependent on the types of electrode materials. The negative shifts of the threshold voltage for the ITO and titanium devices after the 10(4)-s-long drain-bias stress were estimated as 2.06 and 0.96 V, respectively. Superior characteristics of the device using titanium electrodes after a higher temperature annealing process were suggested to originate from the formation of a self-limiting barrier layer at interfaces by nanoscale observations using transmission electron microscopy.
authors.affiliation: Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Yongin, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Jun Yong
authors.initials: JY
authors.lastname: Bak
authors.forename: Sinhyuk
authors.initials: S
authors.lastname: Yang
authors.forename: Min Ki
authors.initials: MK
authors.lastname: Ryu
authors.forename: Sang Hee
authors.initials: SH
authors.lastname: Ko Park
authors.forename: Chi Sun
authors.initials: CS
authors.lastname: Hwang
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Yoon