IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP10
Effects of Annealing Conditions on Doping Efficiency in the Indium Tin Oxide Thin Films Deposited at Low Temperature

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Multilayers and Thin Film Characterization Poster Session
Presenter: J.W. Bae, Sungkyunkwan University, Korea
Authors: J.W. Bae, Sungkyunkwan University, Korea
S.D. Park, Sungkyunkwan University, Korea
D.H. Lee, Sungkyunkwan University, Korea
Y.J. Lee, Sungkyunkwan University, Korea
G.Y. Yeom, Sungkyunkwan University, Korea
Correspondent: Click to Email
Tin-doped indium oxide (ITO) thin films were deposited on glass substrates at low temperature(below 90°C) by a dual oxygen beam assisted evaporator system and the effect of various annealing conditions such as annealing atmosphere and annealing temperature on tin-doping efficiency affecting electrical, physical, and optical properties of the ITO were investigated. The tin composition of the source was varied by mixing indium oxide and tin oxide(0 wt.% ~ 30wt.%). Two rf oxygen sources mounted in the chamber were used for oxygen ion and radical sources, respectively. Atomic percentages of tin in the deposited ITO thin films were investigated by X-ray photoelectron spectroscopy. Carrier density and Hall mobility changed with the doped tin concentration and annealing conditions were measured by Hall effect measurement. Crystallinity, sheet resistance, and optical transmittance were observed by a X-ray diffractometer, a four point probe, and an UV-spectrometer, respectively. Carrier concentration of the undoped indium oxide (0% tin) thin film deposited at the optimum deposition condition of O/In compositions (by controlling the flux ratios of two rf oxygen sources and the evaporation source) was decreased with annealing but Hall mobility was increased from ~20 cm@super 2@/Vs to 105 cm@super 2@/Vs. On the other hand, in the case of tin doped indium oxide (> 0% tin) film deposited at optimum deposition conditions, both the carrier concentration and the mobility were increased with the increase of the annealing temperature and, therefore, the resistivity was decreased from 5 X 10@super -4@ ohm-cm to below 2 X 10@super -4@ ohm-cm due to the increase of tin doping efficiency. Tin atoms located at interstitial sites during the deposition at low temperature appear to move to indium substitutional sites by annealing. It implies that tin atoms in the indium tin oxide deposited at low temperature could act as impurity instead of dopant.