Berlin 2008 – scientific programme
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DS: Fachverband Dünne Schichten
DS 30: Layer Properties: Electrical, Optical and Mechanical Properties
DS 30.2: Talk
Thursday, February 28, 2008, 09:45–10:00, H 2032
Stress-engineering and optical properties of SiO2 and TiO2 thin films grown by dual ion beam deposition — •Carsten Bundesmann, Inga-Maria Eichentopf, Stephan Mändl, and Horst Neumann — Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig
Reduced stress in thin films is a key issue for advanced optical applications, for instance, micro-mirrors. We present results on the influence of additional ion bombardment during growth on the layer stress and optical properties of SiO2 and TiO2 thin films. The thin films are grown by reactive dual ion beam deposition [1]. One ion beam source (sputter source) is used to sputter a target. An additional ion source (assist source) is used to bombard the film during growth. Thereupon, a non-thermal energy contribution is introduced into the top few monolayers, which can be used to tailor thin film properties, for instance, the layer stress [2]. Hence, layer stress and optical properties are investigated depending on the parameters of the sputter and assist source. It is found that the layer stress can be reduced by additional ion bombardment. The most important parameter is the ion energy of the assist source, whereas ion species and ion current have only a minor effect. The refractive index of the thin films changes only slightly and no absorption is introduced upon ion bombardment, which makes these thin films promising candidates for optical applications.
[1] C. Bundesmann, I.-M. Eichentopf, S. Mändl, H. Neumann, in submission.
[2] C. A. Davis, Thin Solid Films 226, 30-34 (1993).