Surface preparation of Si(100) by thermal oxide removal in a chemical vapor environment

The preparation of Si(1 0 0) surfaces in chemical vapor environments suitable for subsequent epitaxial III-V integration by chemical vapor deposition (CVD) involving metal-organic precursors was investigated by surface sensitive instruments accessible through a dedicated sample transfer to ultra high vacuum (UHV). Using X-ray photoelectron spectroscopy for inspection of the chemical surface composition, we verified the ability to obtain clean Si(1 0 0) free of oxygen or other contaminants. Annealing for 30 min in a pure hydrogen atmosphere of 950 mbar pressure was found to be sufficient if the surface temperature reached at least 950 degrees C. We characterized the crucial annealing step comprehensively regarding reliability, dependency on essential process parameters (such as annealing time and surface temperature). Our results verified significant differences to established Si(1 0 0) UHV preparation routines and therefore indicated a major influence of the process gas in the SiO(2) removal process, hence we also considered a chemically active role of the hydrogen ambient in the deoxidation reaction. A complementary assessment of the general structure and the atomic configuration of our CVD-prepared Si(1 0 0) surfaces included low energy electron diffraction and scanning tunnelling microscopy and confirmed atomically flat surfaces with two-domain (2 x 1)/(1 x 2) reconstruction typical for completely deoxidized Si(1 0 0) as well as for a monohydride termination. (C) 2010 Elsevier B.V. All rights reserved.