AVS 45th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoM

Invited Paper TF-MoM1
Atmospheric Pressure Chemical Vapor Deposition of Transparent Conducting Films of Fluorine-Doped Zinc Oxide

Monday, November 2, 1998, 8:20 am, Room 310

Session: Transparent Conductive Oxides
Presenter: R.G. Gordon, Harvard University
Authors: H. Liang, Harvard University
R.G. Gordon, Harvard University
Correspondent: Click to Email
Transparent conducting fluorine doped zinc oxide was deposited as thin films on soda lime glass substrates by atmospheric pressure chemical vapor deposition (CVD) at substrate temperatures of 480@super o@C to 500@super o@C. The precursors diethylzinc, tetramethylethylenediamine and benzoyl fluoride were dissolved in xylene, and this solution was nebulized ultrasonically and then flash vaporized by a carrier gas of nitrogen preheated to 150 @super o@C. Ethanol was vaporized separately, and these vapors were then mixed to form a homogeneous vapor mixture. Good reproducibility was achieved using this new CVD method. Uniform thicknesses were obtained by moving the heated glass substrates through the deposition zone. The best electrical and optical properties were obtained when the precursor solution was aged for more than a week before use. The films were polycrystalline and highly oriented with the c-axis perpendicular to the substrate. More than 90% of the incorported fluorine atoms were electrically active as n-type dopants. The electrical resistivity of the films was as low as 5x10@super -4@ ohm-cm. The mobility was about 45 cm@super 2@/V-s. The electron concentration was up to 3x10@super 20@/cm@super 3@. The optical absorption of the films was about 3-4% at a sheet resistance of 7 ohms/square. The diffuse transmittance was about 10% at a thickness of 650 nm. Amorphous silicon solar cells were deposited using the textured fluorine doped zinc oxide films as the front electrode. The short circuit current was increased over similar cells made with fluorine doped tin oxide.