Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 68: Semiconductor substrates: Epitaxy and growth

O 68.10: Talk

Thursday, March 25, 2010, 12:45–13:00, H42

In situ RAS Analysis of MOVPE prepared GaP/Si(100) heterointerfaces — •Oliver Supplie, Henning Döscher, Sebastian Brückner, Anja Dobrich, Peter Kleinschmidt, Christian Höhn, and Thomas Hannappel — Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

For high-quality optoelectronic devices built on III-V/Si(100) heterostructures, it is crucial to reduce the defect concentration induced by the heterointerface. As an extremely surface sensitive optical probe, reflectance anisotropy spectroscopy (RAS) can be applied in situ in the MOVPE environment. Utilizing RAS, we monitor and characterize the growth of thin GaP layers on a silicon substrate as a model system for III-V/Si(100) heterostructures.
Since RA spectra of the homoepitaxial GaP(100) and heteroepitaxial GaP/Si(100) show characteristic deviations, it is necessary to distinguish the different origins of the RAS signal contributions. Homoepitaxial spectra change with measurement conditions and surface reconstructions. Buried heterointerfaces lead to additional reflections and interference affecting both the reflectance and anisotropy signal. We correct this interference with an empirical method. At III-V/Si(100) heterointerfaces, anti-phase disorder and strain may affect the RAS signal as well. Potentially the interface itself is anisotropic. Applying multiple thin film optical models and reflection simulations, we separate the surface and interface dielectric anisotropy from our measured RAS data.