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A Study on the High-temperature Annealing of ITO Films by Controlling the Oxygen Partial Pressure
Jieun Koo · Youngji Cho · Jiho Chang ∗
Department of Nano Semiconductor Engineering, Korea Maritime University, Busan 606-791
Seunghwan Park · Woong Lee
National Institute for Materials Science, Japan, 305-0044
Hyojong Lee
Department of Materials Science and Engineering, Dong-A University, Busan, 602-714
Sangtae Lee
-61-
Department of Mechatronics Engineering, National Korea Maritime University, Busan, 606-791 (Received 13 October 2011 : revised 9 November 2011 : accepted 9 January 2012)
We have studied about limiting factors of the resistivity in ITO films annealed at high tempera- ture. AFM and transmittance measurements were used to estimate the surface morphology and the transmittance of the ITO films, respectively. In addition, the electrical properties were investigated by using Hall effect and four probe measurements. The resistivity of the ITO film increased from 1.5 × 10
−4Ω·cm to 6 × 10
−4Ω·cm during the annealing at high (600
◦C) temperature, however, it decreased from 1.5 × 10
−4Ω·cm to 1 × 10
−4Ω·cm during the annealing at high (600
◦C) temper- ature under Ar 0.2 MPa pressure. We confirmed by using a theoretical model that resistivity and the carrier concentration depended on both oxygen pressure and the Sn concentration. Finally, the electron backscatter diffraction image was used to characterize the crystallinity of the ITO films to make clear that those observations were not caused by an improved crystal quality.
PACS numbers: 61.72.Cc, 61.16.Bg, 61.72.Ji
Keywords: ITO, High-temperature annealing, High-pressure
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E-mail: jiho [email protected]
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Fig. 1. (Color online) Schematic diagram of experimental system.
Fig. 2. (Color online) AFM images of (a) as-deposited, and (b) annealed at 600
◦C ITO films. (c) Transmittance spectra for as-deposited and annealed samples.
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Fig. 3. Variations of (a) resistivity, and (b) carrier con- centration of high temperature annealed ITO samples without and with external pressure.
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