Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 11: Carbon: Nanotubes, Diamond and Silicon Carbid
HL 11.3: Vortrag
Montag, 26. März 2012, 12:15–12:30, EW 203
H and Si interaction with 4H-SiC surfaces — •Elwira Wachowicz1,2 and Adam Kiejna1 — 1Institute of Experimental Physics, University of Wrocław, Wrocław, Poland — 2Interdisciplinary Centre for Materials Modeling, Warsaw, Poland
Silicon carbide due to its wide band gap, it is suitable for applications related to high power, high frequencies, and high temperatures. The most commonly precursor for silicon in homoepitaxial VPE-growth of SiC is silane. Therefore, the understanding of the Si and H interaction with SiC surfaces is essential to gain better control over the crystal growth process. In this paper the ab initio calculations of the interaction of Si and H atoms with Si- and C-terminated SiC surfaces are presented. The only stable adsorption site on the stechiometric 4H-(0001) and (0001) surfaces is situated on top of the topmost surface atom for H coverages ranging from 0.11 to 1 monolayer (ML). H atom binds stronger on the (0001) with adsorption energy about -6 eV independent of the H coverage. The H adsorption energy on Si-terminated (0001) surface changes from -5.6 eV at 0.11 ML to -5.2 eV at 1 ML. The changes in the first interlayer distances are linear with respect to the H coverage for both surfaces. The molecular dynamic simulations show dissociative adsorption of H2 molecule. Consequently, the study of Si adsorption on partially H covered or H saturated surfaces are performed. Those allow to identify the most favourable Si adsorption sites. The influence of the Si and H coadsorption on the atomic and electronic structure of the 4H-SiC(0001) and (0001) surfaces is analysed.