AVS 49th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP2
The Synthesis and Characterization of Indium Tin Oxide Films by Cesium Assisted Sputtering System at Low Temperature

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Poster Session
Presenter: D.Y. Lee, Yonsei University, Korea
Authors: D.Y. Lee, Yonsei University, Korea
H.K. Baik, Yonsei University, Korea
S.J. Lee, Kyungsung University, Korea
K.M. Song, Konkuk University, Korea
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In this study, we investigated the properties of indium tin oxide (ITO) thin films synthesized by using a cesium assisted sputtering method. Cesium assisted sputtering enables to supply a cesium vapors on the target surface of sputter and generate the negative ions of target materials. The flux and energy of negative ions are independently controlled by the changing target voltage and cesium contents. ITO target (SnO2: In2O3 = 1: 9) was sputtered by mixture gas of argon and oxygen. Oxygen partial pressure, working pressure and other deposition parameters were optimized. RF coupled DC was used as a power source and its voltage was changed from 45 V(only RF) to 350 V(only DC). The temperature of cesium reservoir was varied from 80 to 200 °C. Negative sputtered particles including In, Sn, O and electron were generated from the target surface and accelerated to the substrate by target voltage. We applied additional substrate bias to control deposition energy and flux. The main object of our study is the fabrication of ITO films with low resistivity and high transparency at room temperature by negative ion beam process. The effects of cesium addition not only enable to generate the negative ions by lowering the target work-function but increase the plasma density. From the result of XRD, we concluded that the ion beam effects induced by positive and negative ion enhance the crystallinity of ITO films. In the case of positive bias, negative ions and electrons play a main role in improvement of ITO crystallinity. For the negative bias, argon ions, which fluxes were increased by cesium, promote ITO crystallinity by enhancing the mobility of adatoms on the substrate surface. Also we found that the preferred orientation of ITO films was changed with applied bias. The characterization of deposited ITO films was performed by XRD, four point probe, AFM.