Table of Contents
ISRN Nanomaterials
Volume 2012, Article ID 852405, 11 pages
Research Article

Visible and Deep-Ultraviolet Raman Spectroscopy as a Tool for Investigation of Structural Changes and Redistribution of Carbon in Ni-Based Ohmic Contacts on Silicon Carbide

1Department of Characterisation of Nanoelectronic Structures, Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw, Poland
2Department of Photochemistry and Spectroscopy, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
3Diagnostic Center, V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Pr. Nauky 45, 03028 Kiev, Ukraine
4Laboratory of Growth and Physics of Low Dimensional Crystals, Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
5Department of Micro- and Nanotechnology of Wide Bandgap Semiconductors, Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw, Poland

Received 8 June 2012; Accepted 27 June 2012

Academic Editors: R. Arenal, W. Bao, M. Mirzaei, and G. Speranza

Copyright © 2012 Paweł Borowicz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three samples of 4H polytype of silicon carbide (4H-SiC) covered with the following sequence of layers: carbon/nickel/silicon/nickel/silicon were investigated with micro-Raman spectroscopy. Different thermal treatments of each sample result in differences of carbon layer structure and migration of carbon atoms thorough silicide layer. Two ranges of Raman shift were investigated. The first one is placed between 1000 and 2000 . The main carbon bands D and G are observed in this range. Analysis of the positions of these bands and their intensity ratio enables one to determine the graphitization degree of carbon layer. Additional information about the changes of the carbon layer structure was derived from analysis of 2D band placed around 2700 . Application of deep ultraviolet excitation delivered information about the structure of carbon layer formed on the free surface of silicides and the distribution of the carbon inside the silicide layer.