title: Origin of degradation phenomenon under drain bias stress for oxide thin film transistors using IGZO and IGO channel layers.
abstract: Top-gate structured thin film transistors (TFTs) using In-Ga-Zn-O (IGZO) and In-Ga-O (IGO) channel compositions were investigated to reveal a feasible origin for degradation phenomenon under drain bias stress (DBS). DBS-driven instability in terms of V(TH) shift, deviation of the SS value, and increase in the on-state current were detected only for the IGZO-TFT, in contrast to the IGO-TFT, which did not demonstrate V(TH) shift. These behaviors were visually confirmed via nanoscale transmission electron microscopy and energy-dispersive x-ray spectroscopy observations. To understand the degradation mechanism, we performed ab initio molecular dynamic simulations on the liquid phases of IGZO and IGO. The diffusivities of Ga and In atoms were enhanced in IGZO, confirming the degradation mechanism to be increased atomic diffusion.
authors.affiliation: Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin-si, 446-701, Korea.
authors.forename: Jun Yong
authors.initials: JY
authors.lastname: Bak
authors.affiliation: Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 151-755, Korea.
authors.forename: Youngho
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Electronics &Telecommunications Research Institute (ETRI), Daejeon 305-350, Korea.
authors.forename: Shinhyuk
authors.initials: S
authors.lastname: Yang
authors.affiliation: Electronics &Telecommunications Research Institute (ETRI), Daejeon 305-350, Korea.
authors.forename: Ho-Jun
authors.initials: HJ
authors.lastname: Ryu
authors.affiliation: Electronics &Telecommunications Research Institute (ETRI), Daejeon 305-350, Korea.
authors.forename: Chi-Sun
authors.initials: CS
authors.lastname: Hwang
authors.affiliation: Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 151-755, Korea.
authors.forename: Seungwu
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin-si, 446-701, Korea.
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Yoon