Dresden 2009 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 10: Surface Modification
DS 10.2: Vortrag
Dienstag, 24. März 2009, 11:15–11:30, GER 37
Fundamentals of surfactant sputtering — •Hans Hofsäss and Kun Zhang — II. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-PLatz 1, 37077 Göttingen, Germany
We introduce a new, versatile sputter technique, utilizing the steady state coverage of a substrate surface with up to 1016 cm−2 of foreign or self atoms simultaneously during sputter erosion by combined ion irradiation and atom deposition. These surfactant atoms strongly modify the substrate sputter yield on atomic to macroscopic length scales. The sputter yield can be attenuated in a controlled way from the value of the pure substrate down to zero or even to negative values (growth). Depending on the surfactant-substrate combination, the technique allows enhanced smoothing of surfaces, the generation of surface patterns and nanostructures and shaping of surfaces. The new method may be comparable to ion beam assisted deposition operated beyond the resputtering limit. In this contribution we present examples of surface morphology evolution, smoothing and shaping and shaping of surfaces using surfactant sputtering and we describe analytical and numerical approaches to predict the sputter yield attenuation and the steady state surface coverage. Experiments were done with 5 keV Xe ions at variable incidence angle and fluences up to 1018 cm−2. Sputter yield attenuation is demonstrated for sputtering of Si, SiO2, a-C and Fe with different surfactant species. We analyze in detail sputtering of Si under the influence of Au surfactants, leading to a steady state buried Au silicide layer and enhanced surface smoothing.