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HL: Fachverband Halbleiterphysik

HL 26: Interfaces and Surfaces

HL 26.7: Talk

Monday, March 14, 2011, 17:30–17:45, POT 06

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

High efficient opto-electronic devices based on III-V/Si(100) heterostructures require low defect densities within the active material. Reflection Anisotropy Spectroscopy (RAS) signals from optically isotropic crystals can be related to surfaces, interfaces or defects within the bulk and allow for in situ characterization during metal organic vapor phase epitaxy (MOVPE). The (1×2)-like surface reconstruction of P-rich prepared GaP(100) yields a characteristic RA spectrum [1]. Deviations in the RA spectra of thin GaP/Si(100) films of different thicknesses can originate from (1) internal reflections, i.e. interference, (2) the pure surface anisotropy, (3) anti phase disorder induced at the heterointerface, (4) GaP bulk anisotropies, and (5) a possibly anisotropic GaP/Si(100) interface itself. Those contributions can be separated by optical models [2]. The peak intensities of the pure surface signal allow for improved in situ quantification of the anti phase domain content at the GaP/Si(100) surface and is in agreement with the GaP(100) surface anisotropy. Neglecting GaP-bulk contributions, an interface anisotropy consistent for different GaP film thicknesses can be extracted.

[1] H. Döscher et al. JAP 107 (2010) 123523. [2] T. Yasuda. TSF 313 (1998) 544, O. Hunderi et al. TSF 472 (2005) 261.