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Title: Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors

Abstract

We investigated the positive-bias stress (PBS) instability of thin film transistors (TFTs) composed of different types of first-gate insulators, which serve as a protection layer of the active surface. Two different deposition methods, i.e., the thermal atomic layer deposition (THALD) and plasma-enhanced ALD (PEALD) of Al{sub 2}O{sub 3}, were applied for the deposition of the first GI. When THALD was used to deposit the GI, amorphous indium-gallium-zinc oxide (a-IGZO) TFTs showed superior stability characteristics under PBS. For example, the threshold voltage shift (ΔV{sub th}) was 0 V even after a PBS time (t{sub stress}) of 3000 s under a gate voltage (V{sub G}) condition of 5 V (with an electrical field of 1.25 MV/cm). On the other hand, when the first GI was deposited by PEALD, the ΔV{sub th} value of a-IGZO TFTs was 0.82 V after undergoing an identical amount of PBS. In order to interpret the disparate ΔV{sub th} values resulting from PBS quantitatively, the average oxide charge trap density (N{sub T}) in the GI and its spatial distribution were investigated through low-frequency noise characterizations. A higher N{sub T} resulted during in the PEALD type GI than in the THALD case. Specifically, the PEALD process on a-IGZO layer surface led to an increasingmore » trend of N{sub T} near the GI/a-IGZO interface compared to bulk GI owing to oxygen plasma damage on the a-IGZO surface.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. School of Electrical Engineering, KAIST, Daejeon 34141 (Korea, Republic of)
  2. Department of Material Science and Engineering, KAIST, Daejeon 34141 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22591671
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 108; Journal Issue: 18; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM OXIDES; DAMAGE; DENSITY; DEPOSITION; ELECTRIC FIELDS; GALLIUM; INDIUM; INTERFACES; NOISE; PLASMA; SPATIAL DISTRIBUTION; STRESSES; SURFACES; THIN FILMS; TRANSISTORS; ZINC; ZINC OXIDES

Citation Formats

Kim, Eungtaek, Kim, Choong-Ki, Lee, Myung Keun, Bang, Tewook, Choi, Yang-Kyu, Choi, Kyung Cheol, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr, and Park, Sang-Hee Ko, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr. Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors. United States: N. p., 2016. Web. doi:10.1063/1.4948765.
Kim, Eungtaek, Kim, Choong-Ki, Lee, Myung Keun, Bang, Tewook, Choi, Yang-Kyu, Choi, Kyung Cheol, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr, & Park, Sang-Hee Ko, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr. Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors. United States. doi:10.1063/1.4948765.
Kim, Eungtaek, Kim, Choong-Ki, Lee, Myung Keun, Bang, Tewook, Choi, Yang-Kyu, Choi, Kyung Cheol, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr, and Park, Sang-Hee Ko, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr. Mon . "Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors". United States. doi:10.1063/1.4948765.
@article{osti_22591671,
title = {Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors},
author = {Kim, Eungtaek and Kim, Choong-Ki and Lee, Myung Keun and Bang, Tewook and Choi, Yang-Kyu and Choi, Kyung Cheol, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr and Park, Sang-Hee Ko, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr},
abstractNote = {We investigated the positive-bias stress (PBS) instability of thin film transistors (TFTs) composed of different types of first-gate insulators, which serve as a protection layer of the active surface. Two different deposition methods, i.e., the thermal atomic layer deposition (THALD) and plasma-enhanced ALD (PEALD) of Al{sub 2}O{sub 3}, were applied for the deposition of the first GI. When THALD was used to deposit the GI, amorphous indium-gallium-zinc oxide (a-IGZO) TFTs showed superior stability characteristics under PBS. For example, the threshold voltage shift (ΔV{sub th}) was 0 V even after a PBS time (t{sub stress}) of 3000 s under a gate voltage (V{sub G}) condition of 5 V (with an electrical field of 1.25 MV/cm). On the other hand, when the first GI was deposited by PEALD, the ΔV{sub th} value of a-IGZO TFTs was 0.82 V after undergoing an identical amount of PBS. In order to interpret the disparate ΔV{sub th} values resulting from PBS quantitatively, the average oxide charge trap density (N{sub T}) in the GI and its spatial distribution were investigated through low-frequency noise characterizations. A higher N{sub T} resulted during in the PEALD type GI than in the THALD case. Specifically, the PEALD process on a-IGZO layer surface led to an increasing trend of N{sub T} near the GI/a-IGZO interface compared to bulk GI owing to oxygen plasma damage on the a-IGZO surface.},
doi = {10.1063/1.4948765},
journal = {Applied Physics Letters},
issn = {0003-6951},
number = 18,
volume = 108,
place = {United States},
year = {2016},
month = {5}
}