Design of step composition gradient thin film transistor channel layers grown by atomic layer deposition
- Authors
- Ahn, CH[Ahn, Cheol Hyoun]; Kim, SH[Kim, So Hee]; Yun, MG[Yun, Myeong Gu]; Cho, HK[Cho, Hyung Koun]
- Issue Date
- 1-Dec-2014
- Publisher
- AMER INST PHYSICS
- Citation
- APPLIED PHYSICS LETTERS, v.105, no.22
- Indexed
- SCIE
SCOPUS
- Journal Title
- APPLIED PHYSICS LETTERS
- Volume
- 105
- Number
- 22
- URI
- https://scholarworks.bwise.kr/skku/handle/2021.sw.skku/50483
- DOI
- 10.1063/1.4901732
- ISSN
- 0003-6951
- Abstract
- In this study, we proposed the artificially designed channel structure in oxide thin-film transistors (TFTs) called a "step-composition gradient channel." We demonstrated Al step-composition gradient Al-Zn-O (AZO) channel structures consisting of three AZO layers with different Al contents. The effects of stacking sequence in the step-composition gradient channel on performance and electrical stability of bottom-gate TFT devices were investigated with two channels of inverse stacking order (ascending/descending step-composition). The TFT with ascending step-composition channel structure (5 -> 10 -> 14 at.% Al composition) showed relatively negative threshold voltage (-3.7 V) and good instability characteristics with a reduced threshold voltage shift (Delta 1.4 V), which was related to the alignment of the conduction band off-set within the channel layer depending on the Al contents. Finally, the reduced Al composition in the initial layer of ascending step-composition channel resulted in the best field effect mobility of 4.5 cm(2)/V s. We presented a unique active layer of the "step-composition gradient channel" in the oxide TFTs and explained the mechanism of adequate channel design. (C) 2014 AIP Publishing LLC.
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- Appears in
Collections - Engineering > School of Advanced Materials Science and Engineering > 1. Journal Articles
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