Growth of (0001) AlN Single Crystals Using Carbon-Face SiC as Seeds

Abstract

Growth of AlN single crystals using carbon-polar surface of SiC substrate by PVT growth method has been attempted. AlN growth on the carbon-face was dominated by spiral growth mode under the applied experimental conditions and further, an abrupt interface was observed between AlN layer and the substrate. Broad XRD rocking curve of the sample, taken from bottom part of the crystal, indicates a high density of misfit dislocations near the interface and further a shift of E2(high) phonon mode in the Raman measurements shows a significant misfit stress. The XRD-RC FWHM values of symmetric 002 and asymmetric 102 reflections (top part of the crystal) are 380 and 300 arcsec respectively, whereas the Raman E2(high) peak FWHM value is about 23 cm-1. Decreasing intensity of silicon and carbon LVM peaks with increasing distance from the interface represents the reduction of their incorporation along the crystal length. EPMA analysis confirms the presence of low silicon concentration of 2 wt% in these crystals grown hetero-epitaxially on SiC.