AVS 51st International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA2
Optimization of RF Magnetron Sputter Deposited Indium Tin Oxide (ITO) Transparent Conductors using a Taguchi Statistical Method

Wednesday, November 17, 2004, 2:20 pm, Room 303C

Session: Transparent Conducting Oxides
Presenter: S.I. Jun, The University of Tennessee
Authors: S.I. Jun, The University of Tennessee
P.D. Rack, The University of Tennessee
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In order to optimize the electrical and optical properties of ITO (indium tin oxide) thin films a statistical analysis called the Taguchi design was employed. The sputtering parameters that were considered included RF magnetron sputtering power, oxygen partial pressure, total sputtering pressure, and substrate temperatures. The responses that were considered included sheet resistance, transmission, deposition rate, and etch rate (in 22%HCl+6%CH3COOH+72%H2O). From this design of experiments it was determined that the sheet resistance and transmittance are inversely proportional to each other as a function of the process parameters. The preferred orientation of crystalline ITO film is distinguishably changed with an increase of sputtering temperature and oxygen fraction (O2/O2+Ar) in the sputtering ambient. The change in crystallinity results from the content of incorporated oxygen, which significantly affects the electrical and optical properties of ITO films and causes a rearrangement of atoms to form a preferred closed-packed plane orientation. Finally the microstructure of the ITO films becomes denser with increasing oxygen fraction. As a result of this work, we have successfully achieved low sheet resistance (7.0 ohm/sq.) and high transmittance (~90%) for our targeted 300nm thick films. In this presentation we will briefly review our design of experiments and illustrate our experimental procedure. Subsequently, we will discuss how each process parameter affects each measured response. Finally, will correlate the observed electrical and optical properties of the ITO films to the measured crystal structure and microstructure.