Cent. Eur. J. Phys. • 7(2) • 2009 • 321-326 DOI: 10.2478/s11534-009-0021-0 Central European Journal of Physics On the topographic and optical properties of SiC/SiO 2 surfaces Research Article Stanislav Jureˇ cka 1∗ , Mária Jureˇ cková 2 , Ferdinand Chovanec 3 , Hikaru Kobayashi 5 , Masao Takahashi 4 , Milan Mikula 5 , Emil Pinˇ cík 6 1 DEF FEI Žilina University, Nálepku 1390, 03101 Liptovský Mikuláš, Slovakia 2 Mathematical Institute SAS, Štefánikova 49, 814 73 Bratislava, Slovakia 3 Academy of Armed Forces of Gen. M. R. Štefánik, Demänová 393, 031 01 Liptovský Mikuláš, Slovakia 4 DFCM ISIR Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 587-0047, Japan 5 FCFT, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia 6 Institute of Physics SAS, Dúbravská cesta 9, 84511 Bratislava, Slovakia Received 30 November 2008; accepted 16 February 2009 Abstract: The roughness of the semiconductor surface substantially influences properties of the whole structure, especially when thin films are created. In our work 3C SiC, 4H SiC and Si/a-SiC:H/SiO 2 structures treated by various oxidation a passivation procedures are studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). Surface roughness properties are studied by fractal geometry methods. The complexity of the analysed surface is sensitive to the oxidation and passivation steps and the proposed fractal complexity measure values enable quantification of the fine surface changes. We also determined the optical properties of oxidized and passivated samples by using visual modelling and stochastic opti- mization. PACS (2008): 07.79.Cz; 07.79.Lh; 61.72.Cc; 61.82.Fk; 68.55.ag Keywords: SiC • interface roughness • multifractal systems • AFM, STM • optical properties © Versita Warsaw and Springer-Verlag Berlin Heidelberg. 1. Introduction Silicon carbide has excellent physical properties - high thermal conductivity, high breakdown voltage, high satu- rated electron drift mobility, wide band-gap, etc. It crys- tallizes in more than 200 different types of lattice struc- ∗ E-mail: jurecka@lm.uniza.sk ture. The most important are 3C SiC with a cubic unit cell and 4H SiC with a hexagonal unit cell structure. SiC is much more chemically stable compared to Si and there- fore a higher temperature (above 1100°C) is necessary for conventional thermal oxidation [1–3]. Carbon clusters are formed at the SiC/SiO 2 interfaces during this high temper- ature oxidation and they strongly influence the interface state density, which is greater than one order of magni- tude higher than in Si [3–5]. High temperature oxidation degrades the interfacial and surface properties, the sur- 321 Unauthenticated Download Date | 2/26/20 1:16 AM