Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 10: Semiconductor surfaces and interfaces

O 10.6: Vortrag

Montag, 27. März 2006, 16:15–16:30, PHY C213

Photothermal patterning of H-terminated silicon substrates: Writing nanostructures with a micron-sized laser beam — •Rafael Bautista, Thorsten Balgar, Steffen Franzka, Nils Hartmann, and Eckart Hasselbrink — Universität Duisburg-Essen, Fachbereich Chemie, Universitätsstr. 5, 45141 Essen

A focused beam of an argon ion laser at a wavelength of 514 nm is used for rapid large-area patterning of H-terminated Si(100) substrates under ambient conditions [1]. The technique allows for the preparation of well-confined, ultrathin oxide structures with a lateral dimension significantly below the diffraction limited laser spot diameter of the optical setup. In particular, at a focal spot diameter of about 2.5 µm oxide lines with a width from several microns down to 300 nm are prepared. At even smaller spot diameters structures with a lateral dimension below 200 nm are reached. The patterning experiments under ambient conditions are complemented by investigations in an ultrahigh vacuum environment. A simple thermokinetic analysis of the data allows to estimate effective kinetic parameters of the patterning process and reproduce the experimentally observed functional dependence of the line width on the incident laser power and the writing speed. The underlying highly superlinear dependence of the overall patterning process on the laser intensity is traced back to the interplay between the laser-induced transient local temperature rise and the thermally activated hydrogen desorption.

[1] T. Balgar, S. Franzka, N. Hartmann, E. Hasselbrink, Langmuir 20 (2004) 3525.