Regensburg 2010 – wissenschaftliches Programm
HL 3.4: Vortrag
Montag, 22. März 2010, 11:00–11:15, H14
In situ characterization of VPE prepared Si(100) surfaces via RAS — •Sebastian Brückner, Henning Döscher, Anja Dobrich, Oliver Supplie, Christian Höhn, and Thomas Hannappel — Helmholtz- Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin
The epitaxial growth of III-V semiconductors on silicon substrates is a major challenge for the integration of opto- and micro-electronic devices. The first crucial step in the III-V on Si hetero epitaxy consists of a substrate preparation ensuring complete removal of oxides and a suitable atomic surface structure. It has been shown in UHV that reflection anisotropy spectroscopy (RAS) is a powerful tool to characterize Si(100) surfaces. The spectra of nominal and vicinal Si(100) substrates differ strongly due to the influences of terrace and step structures on the signal. Also adsorbates like hydrogen and oxygen show a strong impact on the spectra. We applied in situ RAS in our MOVPE reactor to characterize and control the preparation of Si(100) with 0.1°, 2° and 6° offcuts towards <111> direction. During the oxide removal process the RA spectra change from a baseline spectrum of the oxidized surface to the typical clean Si(100) spectrum. We were able to observe this change in situ by transient RAS measurements. In addition the adsorption of hydrogen on the Si surface during cool down was studied. A dedicated contamination free sample transfer system from MOVPE environment to UHV enabled us to benchmark the RA spectra with results from various surface science instruments.