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Sumathi, R. Radhakrishnan; Paun, Matthias (2013): Growth of (0001) AlN single crystals using carbon-face SiC as seeds. In: Materials Science Forum, Vol. 740-742: pp. 99-102
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Growth of AlN single crystals using carbon-polar surface of SiC substrate by the physical vapour transport (PVT) growth method has been attempted. AlN growth on the carbon-face is dominated by spiral growth mode under the applied experimental conditions and further, the interface between AlN layer and the substrate is found to be sharp. Broad x-ray diffraction rocking curve (XRD-RC) of the sample, taken from bottom part of the crystal, indicates a high density of misfit dislocations near the interface and E2(high) phonon mode shift in the Raman measurements shows a significant misfit stress. The XRD-RC full-width at half-maximum (FWHM) values of symmetric 0002 and asymmetric 10-12 reflections (top part of the crystal) are 380 and 300 arcsec respectively, whereas the E2(high) peak FWHM value is about 23 cm^-1. Decreasing intensity of local vibrational modes (LVM) of silicon and carbon with increasing distance from the interface represents a reduction of their incorporation along the crystal length. Electron probe microanalysis measurement (EPMA) confirms the presence of low silicon concentration of 2 wt% in these heteroepitaxially grown AlN crystals on SiC.