Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.67: Poster

Monday, March 26, 2007, 17:30–20:30, Poster C

Laser-assisted Carbon Burning (LACB) - Removal of Organic Impurities at Room Temperature — •Jonas Bock, Andreas Aßmuth, Ulrich Abelein, Torsten Sulima, and Ignaz Eisele — Universität der Bundeswehr München, Institut für Physik, 85579 Neubiberg, Germany

The cleaning of silicon surfaces is one of the most important issues for the fabrication of novel semiconductor devices. Taking into account out-diffusion of dopants or mechanical stress of SiGe hetero structures, high temperatures have to be avoided. Therefore a maximum processing temperature of T=700 ^∘C must not be exceeded by any processing step, which applies accordingly to the removal of the two main contaminants of Si wafers - organic impurities and the native oxide. One possible approach is using gaseous precursors excited by plasma or laser. Because high energy ions caused by plasma excitation roughen the surface and laser beam radiation perpendicular to the substrate may lead to high temperatures, the investigations have been carried out using an excimer laser combined with an UHV system where the laser beam is guided parallel to the wafer. An in-situ cleaning step based on laser excitation of oxygen will be presented. The influence of temperature, oxygen partial pressure and laser energy have been studied, the effectiveness will be shown by SIMS analysis and I-V-measurements of devices, that were built on LACB cleaned substrates.