Dresden 2006 – scientific programme
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O: Oberflächenphysik
O 20: Epitaxy and growth II
O 20.7: Talk
Tuesday, March 28, 2006, 12:45–13:00, WIL B321
Optical in situ monitoring of deoxidation of III-V-semiconductors in MOVPE — •A. Oestereich1, C. Kaspari1, M. Pristovsek1, and W. Richter2 — 1Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin — 2Università degli Studi di Roma "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Roma, Italy
In epitaxial growth the removal of the unavoidable oxide layer on the substrat is a very important matter. We have studied thermal oxide desorption in MOVPE with Reflectance Anisotropy Spectroscopy (RAS) and Spectroscopic Ellipsometry (SE). The aim was to clarify the influence of the carrier gas, precursor, temperature ramp and of pre-growth treatment like wet etching. In all studied cases we observed a gradual transition of the RAS signal in a temperature range of 50K to 200K between the beginning of oxide removal and the formation of a clean reconstruction. In the case of InAs the deoxidation starts approximatly at 240∘C and is complete at ∼480∘C. For GaP the start temperature is ∼510∘C and the clean surface is formed around 620∘C. The desorption temperature increases with the bond energy of the material.