AVS 50th International Symposium
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM9
Surface Characteristics of the Remote Plasma-treated ITO

Friday, November 7, 2003, 11:00 am, Room 328

Session: Oxide Surfaces and Interfaces
Presenter: S. Kim, Hanyang University, Korea
Authors: S. Kim, Hanyang University, Korea
H. Seo, Hanyang University, Korea
Y. Kim, Pusan National University, Korea
K. Kim, LG Electronics
Y. Tak, LG Electronics
H. Jeon, Hanyang University, Korea
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Indium tin oxide (ITO) is an essential material in fabrication of organic light emitting devices (OLEDs). ITO functions as a hole injector into organic material and the injection efficiency is influenced by the work function of ITO anode surface. Work function of the ITO surface primarily depends on carbon and oxygen concentration. Particularly, carbon contaminants of ITO surface should be removed as much as it could be, because it results in the defect of bonding structure and increases in the sheet resistance of ITO. We investigated the removal of surface carbon contaminants using the oxygen and hydrogen plasma and examined the change of chemical composition and electrical properties of ITO after plasma treatments. ITO film was coated on glass to a thickness of about 1600Å and had a sheet resistance of about 10 Ω/□. And these ITO glass specimens were not pre-cleaned before plasma cleaning to demonstrate effects using plasma treatments only. The remote RF plasma cleaning chamber and the surface analysis system were connected each other by an ultra-high vacuum transfer system for the in-situ analysis. The carbon residues were almost removed below the detection limit of XPS after remote plasma cleaning at 50W. In XPS analysis for Sn3d@sub 5/2@, Two peaks were completely resolved. These resolved peaks indicated respectively Sn@super 2+@ and Sn@super 4+@. The peak intensity of Sn@super 4+@ was reduced on ITO surfaces which was treated by plasma. Work function on ITO surface increased by oxygen plasma treatment and decrease by hydrogen plasma treatment. It also showed that the oxygen concentration affected much more than carbon contamination at the work function of the ITO surfaces. @FootnoteText@ @footnote 1@H. Y. Yu, X.D. Feng, D. Grozea, and Z. H. Lu, R. N. S. Sodhi, A-M. Hor and H. Aziz, Appl. Phys. Lett., 78, 2595-2597 (2001).