Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 19: Semiconductor Substrates: Structure, Adsorption and Growth

O 19.3: Poster

Montag, 7. März 2016, 17:00–19:30, Poster A

Hydrogen etching of SiC(0001): STM study of an epitaxy template — •Maximilian Bauernfeind, Felix Reis, Stefan Glass, Julian Aulbach, Ralph Claessen, and Jörg Schäfer — Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, 97074 Würzburg, Germany

The hexagonal (0001) surface of silicon carbide (SiC) offers a huge playground for the epitaxy of a large variety of different materials, which has received little attention until now. One challenging aspect is the growth of high-Z atom lattices made out of, e.g., Sn or Bi in the monolayer regime, which may potentially form graphene analogs with a hexagonal structure. Because of the strong spin-orbit coupling in this class of materials, topological protected edge states can emerge.

To enable epitaxy of such promising high-Z materials, one has to focus on the substrate quality, and prepare defect-free and well-ordered flat surfaces. In-situ gas phase etching can thereby attack the inert SiC much better than chemical pathways. It is performed at temperatures above 1000 ^∘C in a hydrogen atmosphere.

To get new insights of this substrate on the atomic scale, we will address in general the differences between the etching treatments in a stationary and a flowing hydrogen atmosphere by means of scanning tunneling microscopy. To be specific, we will demonstrate the effects of different hydrogen flow values, including addition of the inert gas helium, as well as the influence of the substrate temperature. The results will be analyzed regarding large-scale terrace formation and defect density.