AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP29
Optimization of the Reflectivity of Magnetron Sputter Deposited Silver Films

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: M. Vergöhl, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
Authors: M. Vergöhl, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
N. Malkomes, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
B. Szyszka, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
F. Neumann, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
T. Matthée, Fraunhofer Institute for Surface Engineering and Thin Films, Germany
G. Bräuer, Leybold Systems GmbH, Germany
Correspondent: Click to Email
Silver films were deposited by means of dc and mid-frequency (MF) magnetron sputter deposition on floatglass in order to achieve a maximum reflectivity over the entire visual and infrared spectral range. The films were investigated by means of ex-situ and in-situ spectroscopic ellipsometry, reflectivity, conductivity measurements, and atomic force microscopy (AFM). The following deposition parameters were varied: mid-frequency and dc-technique, power density, sputtering pressure, substrate temperature, sputtering gas (Ar, Kr, Ne), nitrogen and oxygen residual gas, and film thickness. With the aid of in-situ spectroscopic ellipsometry, it can be shown that for certain process parameters an optimum layer thickness exists for achieving a maximum reflectivity in the visual spectral range. With increasing thickness, optical losses come into play which are due to the formation of larger grains. This optimum layer thickness is smaller in the films deposited in the MF mode, indicating a smoother surface and smaller grain size compared to the DC mode. As an optimum value, a reflectivity of R=99.3% is achieved. The resistivity of this film was found to be @rho@=2.4 µ@Omega@ cm. The measured reflectivity is close to the theoretical value, which was determined from the Drude-Lorentz fit parameters with respect to the resistivity. The measured reflectivity of the sputter deposited films will be compared to thin films which are prepared by e-beam evaporation.