Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 31: Surface Chemical Reactions and Heterogeneous Catalysis I

O 31.8: Talk

Tuesday, March 27, 2007, 17:30–17:45, H38

Photothermal patterning of H-terminated Si(100) substrates: Experiments in an ultrahigh vacuum environment — •Mareike Mathieu, Rafael Bautista, Nils Hartmann, and Eckart Hasselbrink — Fachbereich Chemie, Universität Duisburg-Essen, Universitätstr. 5, 45117 Essen

Silicon substrates are widely used as platforms in many micro- and nanofabrication schemes, e.g. in order to build up organic templates [1,2]. For this purpose suitable patterning techniques are needed. In a previous study, we reported a simple laser-assisted technique for patterning of H-terminated Si(100) substrates under ambient conditions [1]. A focused beam of an argon ion laser at a wavelength of 514 nm is used to create well-confined, ultra-thin oxide structures. Despite a laser spot diameter of about 2.5 microns line widths down to 300 nm are reached. In order to investigate the underlying mechanism, recent experiments were carried out at well-defined conditions in an ultrahigh vacuum environment. HF etched Si(100) substrates, Si(100)-(1x1)-dihydride and Si(100)-(2x1)-monohydride adsorbate phases were prepared for patterning. On the basis of the results, the nonlinear dependence of the patterning process on the laser intensity is traced back to the interplay between the laser-induced temperature rise and the thermally activated hydrogen desorption.

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

[2] D. Dahlhaus, S. Franzka, E. Hasselbrink, N. Hartmann, Nano Letters 6 (2006) 2358