Growth monitoring of GaAsSb:C/InP heterostructures with reflectance anisotropy spectroscopy

F. Brunner^a, S. Weeke^b, M. Zorn^a and M. Weyers^a

^a Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
^b Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany

Published in:
Journal of Crystal Growth 272 (2004) 111-117.
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Abstract:
Using time-resolved reflectance anisotropy spectroscopy (RAS) we studied insitu the dynamics of surface processes of Sb-covered GaAs(100) and InP(100) under metalorganic vapour-phase epitaxy conditions. Both Sb removal during a hydride purge and Sb incorporation during GaAs and InP over growth we remonitored enabling the investigation of group V exchange reactions.
Sb surface layers are found to be much more stable during purge with PH₃ as compared to AsH₃. Estimated activation energies are 2.5eV for the Sb-P exchange processes and 1.1eV for the Sb-As exchange reactions. These values reflect the low volatility of Sb compared to other group V adsorbates. During InP overgrowth Sb is rapidly buried at temperatures of 510°C and below while it is rather persistent on the surface at temperatures of 550°C and above. This transition indicates the existence of a highly mobile quasi-liquid InSb surface layer at temperatures above its melting point (~525°C).

Keywords:
A1. Reflection anisotropy spectroscopy; A1. Segregation; A3. Metalorganic vapour-phase epitaxy; B1. Antimonides

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