title: Density of states-based design of metal oxide thin-film transistors for high mobility and superior photostability.
abstract: A novel method to design metal oxide thin-film transistor (TFT) devices with high performance and high photostability for next-generation flat-panel displays is reported. Here, we developed bilayer metal oxide TFTs, where the front channel consists of indium-zinc-oxide (IZO) and the back channel material on top of it is hafnium-indium-zinc-oxide (HIZO). Density-of-states (DOS)-based modeling and device simulation were performed in order to determine the optimum thickness ratio within the IZO/HIZO stack that results in the best balance between device performance and stability. As a result, respective values of 5 and 40 nm for the IZO and HIZO layers were determined. The TFT devices that were fabricated accordingly exhibited mobility values up to 48 cm(2)/(V s), which is much elevated compared to pure HIZO TFTs (∼13 cm(2)/(V s)) but comparable to pure IZO TFTs (∼59 cm(2)/(V s)). Also, the stability of the bilayer device (-1.18 V) was significantly enhanced compared to the pure IZO device (-9.08 V). Our methodology based on the subgap DOS model and simulation provides an effective way to enhance the device stability while retaining a relatively high mobility, which makes the corresponding devices suitable for ultradefinition, large-area, and high-frame-rate display applications.
authors.affiliation: Display Device Lab, Samsung Advanced Institute of Technology, Yongin, 446-712, Republic of Korea.
authors.forename: Hyun-Suk
authors.initials: HS
authors.lastname: Kim
authors.forename: Joon Seok
authors.initials: JS
authors.lastname: Park
authors.forename: Hyun-Kwang
authors.initials: HK
authors.lastname: Jeong
authors.forename: Kyoung Seok
authors.initials: KS
authors.lastname: Son
authors.forename: Tae Sang
authors.initials: TS
authors.lastname: Kim
authors.forename: Jong-Baek
authors.initials: JB
authors.lastname: Seon
authors.forename: Eunha
authors.initials: E
authors.lastname: Lee
authors.forename: Jae Gwan
authors.initials: JG
authors.lastname: Chung
authors.forename: Dae Hwan
authors.initials: DH
authors.lastname: Kim
authors.forename: Myungkwan
authors.initials: M
authors.lastname: Ryu
authors.forename: Sang Yoon
authors.initials: SY
authors.lastname: Lee