Characterization of Aluminum Doped Zinc Oxide Thin Films Fabricated by Rectangular Filtered Vacuum Arc Deposition on Large Flat Glass Substrates

摘要

Filtered vacuum arc deposition (FVAD) of Al-doped Zinc Oxide (AZO) may be an advantageous alternative to present transparent conductive coatings. The objectives of this study were to determine the effects of deposition parameters on the properties of AZO films produced in a large FVAD system. Film thickness distribution, electrical properties, optical properties, crystalline structure, chemical concentration and stability were determined. The films were deposited using a Zn-9 %at Al cathode, in background oxygen pressures of P_(O2)= 6,7, and 8 mTorr, onto 400 × 420 mm glass or 40 glass microscope slide substrates. The substrates were transported through the plasma beam at the output of a macroparticle filter at a velocity of 4 cm/s for 8, 10 or 12 passes. The crystalline structure and the optical and electrical characteristics of the films improved with increasing P_(O2) The thickness distribution was a skewed parabolic across the substrate in the X-direction, perpendicular to the substrate motion direction. The dynamic deposition rate of the films, in the center area of the substrate, and deposited at P_(O2) = 6, 7, and 8 mTorr, were 185, 166 and 132 nm m/min, respectively. The average Al concentration was 0.14-0.18 %at (50-70 times lower that in the cathode material) and also varied with X - higher Al concentrations were measured in the central area having the thicker film. Best electrical and optical characteristics were measured in films deposited at P_(O2)=8 mTorr. These films had a transparency (T) of 85 %, resistivity (ρ) of 2.2 × 10~(-3) Ω cm, free carrier concentration (n_c) of 3.6 × 10~(19) cm~(-3) and mobility (μ) of 67 cm~2V~(-1)s~(-1).