Density of States-Based Design of Metal Oxide Thin-Film Transistors for High Mobility and Superior Photostability

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• 作者：Hyun-Suk Kim ; Joon Seok Park ; Hyun-Kwang Jeong ; Kyoung Seok Son ; Tae Sang Kim ; Jong-Baek Seon ; Eunha Lee ; Jae Gwan Chung ; Dae Hwan Kim ; Myungkwan Ryu ; Sang Yoon Lee
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2012
• 出版时间：October 24, 2012
• 年：2012
• 卷：4
• 期：10
• 页码：5416-5421
• 全文大小：439K
• 年卷期：v.4,no.10(October 24, 2012)
• ISSN：1944-8252

文摘

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 cm²/(V s), which is much elevated compared to pure HIZO TFTs (13 cm²/(V s)) but comparable to pure IZO TFTs (59 cm²/(V s)). Also, the stability of the bilayer device (鈭?.18 V) was significantly enhanced compared to the pure IZO device (鈭?.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.

Keywords:

metal oxide thin-film transistors; hafnium-indium-zinc-oxide; indium-zinc-oxide; photostability; density-of-states