Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 10: Semiconductor Substrates: Epitaxy and Growth

O 10.5: Talk

Monday, February 25, 2008, 14:15–14:30, MA 042

The Influence of Carbon Contaminations in Silicon Epitaxy — •Oliver Senftleben, Peter Iskra, Tanja Stimpel-Lindner, Dorota Kulaga-Egger, Ignaz Eisele, and Hermann Baumgärtner — Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85577 Neubiberg

Thermal desorption of the native oxide is a well-known process but leads to an increase in surface roughness and to the formation of SiC. HF treatment, however, leads to a strong carbon contamination of the surface. Both treatments influence subsequent epitaxial overgrowth differently, which will be shown troughout this contribution.

The influence of carbon contaminations on silicon epitaxy strongly depends on its distribution on the silicon surface. A rather homogenous distribution still allows epitaxial layers of good quality. This will be shown by STM and SIMS. An even higher degree of carbon contamination after HF treatment still allows epitaxial layers of good electrical quality, evaluated by I-V measurements of CVD grown pin diodes with a very high amount of carbon at the interface, measured by SIMS.

Thermal desorption of the native oxide covered by carbon contaminats at temperatures between 800 °C and 900 °C lead to the formation of SiC, which acts as a nucleation site for the Si-monomer and to the formation of stable pyramidal structures with heights up to several 10 nanometers as well as polysilicon, which is demonstrated by STM, SEM and AES measurements. This causes a reduction of the epitaxial quality of subsequent layers.