Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 34: Poster I: III-V Semiconductors

HL 34.2: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D2

In situ characterization of homo- and heteroepitaxial GaP(100) surfaces by reflectance anisotropy spectroscopy — •Sebastian Brückner, Henning Döscher, Oliver Supplie, Anja Dobrich, Peter Kleinschmidt, and Thomas Hannappel — Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin

Reflectance anisotropy spectroscopy (RAS) is an extremely surface sensitive optical probe applicable for in situ measurements during metal-organic vapour phase epitaxy (MOVPE). Here, we study gallium phosphide deposition on Si(100) as an exemplary model system for the heteroepitaxial III-V growth on non-polar substrates.

The created heterointerface gives rise to the formation of anti-phase domains (APDs) according to the step structure of the substrate. The quantitative in situ RAS control over this crucial defect mechanism requires at first reliable surface preparation and the correct consideration of all influences on the structure and intensity of the characteristic spectra such as surface reconstruction, atomic order or temperature.

Then the reliable in situ quantification of the ADP content of a sample is still corrupted by interferences of the signal with interfacial reflections. These mainly affect the normalization of the RAS signal, which we were able to correct by the empirical calculation of the appropriate relative reflectance. Minor deviations still occur due to the specific anisotropy of the III-V/Si heterointerface, which may be derived by optical simulations.