4H-SiC Surface Structures and Oxidation Mechanism Revealed by Using First-Principles and Classical Molecular Dynamics Simulations

Abstract:

The 4H-SiC(000-1)_C and (0001)_Si surface reconstructed structures and the oxidation processes of these surfaces are investigated using a first-principles calculation method. The most stable reconstructed 4H-SiC(000-1)_C and (0001)_Si surfaces have p-bonded chains. In the topmost SiC bilayer, half of Si and C atoms exchange their positions and C-C or Si-Si bonds formed densely below the surfaces. When we place a SiO₂ layer on the p-bonded chain (000-1)_C surface, C-C bonds are formed more densely below the interface. We simulate a sequence of O₂ molecules arrivals at an interface of tridymite-phase-SiO₂ and 4H-SiC(000-1)_C. Dissociated O atoms at the interface tended to make bonds with Si atoms. The C-C bonds in the SiC substrate break easily and a local C surface occasionally appears. We have examined how the surface structure changes through an O₂ molecule exposure by using a classical molecular dynamics simulation program and confirmed the formation of C-C bonds below the surface and the interface.

• Periodical: Materials Science Forum (Volume 858)
• Pages: 429-432
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.858.429
• Online since: May 2016
• Authors: Takahiro Yamasaki*, Nobuo Tajima, Tomoaki Kaneko, Nobutaka Nishikawa, Jun Nara, Tatsuo Schimizu, Koichi Kato, Takahisa Ohno
• Keywords: 4H-SiC, First-Principles, Molecular Dynamics Simulation, Oxidation, Surface Structures

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