Improvement of Electrical Characteristics and Stability of Amorphous Indium Gallium Zinc Oxide Thin Film Transistors Using Nitrocellulose Passivation Layer.

Author(s) Shin, K.Yup; Tak, Y.Jun; Kim, W.G.; Hong, S.; Kim, H.Jae
Journal ACS Appl Mater Interfaces
Date Published 2017 Apr 19

In this research, nitrocellulose is proposed as a new material for the passivation layers of amorphous indium gallium zinc oxide thin film transistors (a-IGZO TFTs). The a-IGZO TFTs with nitrocellulose passivation layers (NC-PVLs) demonstrate improved electrical characteristics and stability. The a-IGZO TFTs with NC-PVLs exhibit improvements in field-effect mobility (μFE) from 11.72 ± 1.14 to 20.68 ± 1.94 cm(2)/(V s), threshold voltage (Vth) from 1.85 ± 1.19 to 0.56 ± 0.35 V, and on/off current ratio (Ion/off) from (5.31 ± 2.19) × 10(7) to (4.79 ± 1.54) × 10(8) compared to a-IGZO TFTs without PVLs, respectively. The Vth shifts of a-IGZO TFTs without PVLs, with poly(methyl methacrylate) (PMMA) PVLs, and with NC-PVLs under positive bias stress (PBS) test for 10,000 s represented 5.08, 3.94, and 2.35 V, respectively. These improvements were induced by nitrogen diffusion from NC-PVLs to a-IGZO TFTs. The lone-pair electrons of diffused nitrogen attract weakly bonded oxygen serving as defect sites in a-IGZO TFTs. Consequently, the electrical characteristics are improved by an increase of carrier concentration in a-IGZO TFTs, and a decrease of defects in the back channel layer. Also, NC-PVLs have an excellent property as a barrier against ambient gases. Therefore, the NC-PVL is a promising passivation layer for next-generation display devices that simultaneously can improve electrical characteristics and stability against ambient gases.

DOI 10.1021/acsami.7b00257
ISSN 1944-8252
Citation ACS Appl Mater Interfaces. 2017;9(15):1327813285.

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