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

Authors :
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
Source :
Journal of Materials Science; Aug2019, Vol. 54 Issue 16, p11145-11156, 12p, 4 Charts, 8 Graphs
Publication Year :
2019

Abstract

We report the hydrogen barrier performance of sputtered La<subscript>2</subscript>O<subscript>3</subscript> 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. La<subscript>2</subscript>O<subscript>3</subscript>, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La<subscript>2</subscript>O<subscript>3</subscript> is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La<subscript>2</subscript>O<subscript>3</subscript> 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, O<subscript>2</subscript> 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 La<subscript>2</subscript>O<subscript>3</subscript> films. The results demonstrate that La<subscript>2</subscript>O<subscript>3</subscript> films grown with low RF power and low O<subscript>2</subscript> 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00222461
Volume :
54
Issue :
16
Database :
Complementary Index
Journal :
Journal of Materials Science
Publication Type :
Academic Journal
Accession number :
136714887
Full Text :
https://doi.org/10.1007/s10853-019-03685-4