Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor

Yujin Lee, Chong Hwon Lee, Taewook Nam, Sanghun Lee, Il Kwon Oh, Joon Young Yang, Dong Wook Choi, Choongkeun Yoo, Ho jin Kim, Woo Hee Kim, Hyungjun Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs.

Original languageEnglish
Pages (from-to)11145-11156
Number of pages12
JournalJournal of Materials Science
Volume54
Issue number16
DOIs
Publication statusPublished - 2019 Aug 30

Fingerprint

Thin film transistors
Hydrogen
Amorphous films
Partial pressure
Thin films
Electronegativity
Reactive sputtering
Magnetron sputtering
Refractive index
Degradation
Microstructure
Substrates
Processing

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Lee, Yujin ; Lee, Chong Hwon ; Nam, Taewook ; Lee, Sanghun ; Oh, Il Kwon ; Yang, Joon Young ; Choi, Dong Wook ; Yoo, Choongkeun ; Kim, Ho jin ; Kim, Woo Hee ; Kim, Hyungjun. / Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor. In: Journal of Materials Science. 2019 ; Vol. 54, No. 16. pp. 11145-11156.
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abstract = "We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs.",
author = "Yujin Lee and Lee, {Chong Hwon} and Taewook Nam and Sanghun Lee and Oh, {Il Kwon} and Yang, {Joon Young} and Choi, {Dong Wook} and Choongkeun Yoo and Kim, {Ho jin} and Kim, {Woo Hee} and Hyungjun Kim",
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Lee, Y, Lee, CH, Nam, T, Lee, S, Oh, IK, Yang, JY, Choi, DW, Yoo, C, Kim, HJ, Kim, WH & Kim, H 2019, 'Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor', Journal of Materials Science, vol. 54, no. 16, pp. 11145-11156. https://doi.org/10.1007/s10853-019-03685-4

Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor. / Lee, Yujin; Lee, Chong Hwon; Nam, Taewook; Lee, Sanghun; Oh, Il Kwon; Yang, Joon Young; Choi, Dong Wook; Yoo, Choongkeun; Kim, Ho jin; Kim, Woo Hee; Kim, Hyungjun.

In: Journal of Materials Science, Vol. 54, No. 16, 30.08.2019, p. 11145-11156.

Research output: Contribution to journalArticle

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T1 - Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor

AU - Lee, Yujin

AU - Lee, Chong Hwon

AU - Nam, Taewook

AU - Lee, Sanghun

AU - Oh, Il Kwon

AU - Yang, Joon Young

AU - Choi, Dong Wook

AU - Yoo, Choongkeun

AU - Kim, Ho jin

AU - Kim, Woo Hee

AU - Kim, Hyungjun

PY - 2019/8/30

Y1 - 2019/8/30

N2 - We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs.

AB - We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs.

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