Density of states-based design of metal oxide thin-film transistors for high mobility and superior photostability

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

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

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.

Original languageEnglish
Pages (from-to)5416-5421
Number of pages6
JournalACS Applied Materials and Interfaces
Volume4
Issue number10
DOIs
StatePublished - 24 Oct 2012

Keywords

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

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