Papers by Author: Leszek Konczewicz

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Authors: Pawel Kwasnicki, Roxana Arvinte, Hervé Peyre, Marcin Zielinski, Leszek Konczewicz, Sylvie Contreras, Jean Camassel, Sandrine Juillaguet
Abstract: In this work, we focus on heavily aluminum (Al) doped 4H-SiC samples. We compare the effect of the Al concentration and Hall carrier concentration on the Raman spectra in a large frequency range. The Al concentration measured by Secondary Ion Mass Spectrometry ranged from 2×1016 to 8.4×1019 cm-3 while the electrical measurement give a carrier concentration up to 5×1019 Al×cm-3. On the Raman spectra, three different frequency domains have been analysed: i) at high frequency where we consider the change in longitudinal optical phonon-plasmon coupled mode; ii°) at low frequency where we consider the continuum of electronic transitions and iii°) finally, considering the Fano interference effect between the continuum of electronic transitions and the Folded Transverse Acoustic phonon modes. This analysis is applied to comment a Raman spectra mapping collected on a 4H-SiC 2 inch wafer.
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Authors: Sylvie Contreras, Marcin Zielinski, Leszek Konczewicz, Caroline Blanc, Sandrine Juillaguet, Ralf Müller, Ulrike Künecke, Peter J. Wellmann, Jean Camassel
Abstract: We report on investigation of p-type doped, SiC wafers grown by the Modified- Physical Vapor Transport (M-PVT) method. SIMS measurements give Al concentrations in the range 1018 to 1020 cm-3, with weak Ti concentration but large N compensation. To measure the wafers’ resistivity, carrier concentration and mobility, temperature-dependant Hall effect measurements have been made in the range 100-850 K using the Van der Pauw method. The temperature dependence of the mobility suggests higher Al concentration, and higher compensation, than estimated from SIMS. Additional LTPL measurements show no evidence of additional impurities in the range of investigation, but suggest that the additional compensation may come from an increased concentration of non-radiative centers.
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