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HL: Halbleiterphysik
HL 33: III-V Halbleiter I
HL 33.4: Talk
Wednesday, March 10, 2004, 19:00–19:15, H14
MOVPE in-situ monitoring and analysis of substrate deoxidation of GaSb(100) — •Kristof Möller1, Lars Töben1, Zadig Kollonitsch1, Christoph Giesen2, Michael Heuken2, Frank Willig1, and Thomas Hannappel1 — 1Hahn-Meitner-Institut, SE-4, Glienicker Str. 100, D-14109 Berlin, Germany — 2AIXTRON AG, Kackertstr. 15-17, D-52072 Aachen, Germany
The crucial deoxidation of GaSb prior to epitaxy was investigated in-situ with reflectance anisotropy spectroscopy (RAS). Substrates were annealed in an AIX-200 MOVPE reactor in the presence of triethylantimony in H2 ambient. Deoxidation was carried out between 475−575∘C. RAS signals show the progress in deoxidation for different chemical pre-treatments, annealing temperatures, and annealing times. No-dqEpi-readyNo-dq substrates annealed without any chemical pre-treatment showed the formation of anisotropic, nanometer-scaled 3D-structures during deoxidation. The anisotropic roughness was observed in-situ as an unusual increase of the RAS signal. This enhanced RAS signal vanished after deoxidation was completed. RAS Signals showed the absence of roughness for chemically pre-treated substrates. The surface of the substrates was investigated with UPS and XPS spectroscopy. The RAS-correlated information on electronic structure and chemical surface composition is essential for understanding and improving the deoxidation process of GaSb.