Properties of AlN Layers Grown on SiC Substrates in Wide Temperature Range by HVPE

AlN epitaxial layers were grown on 6H-SiC on-axis substrates by HVPE. The deposition was performed directly on (0001)Si face of the substrates without any buffer layer. Growth temperature was varied from 700 to 1200 °C. Thickness of AlN layers ranged from 0.1 to 1 μm. AlN surface morphology was studied by atomic force microscopy (AFM). The minimum value of Ra roughness was obtained for 0.1 μm thick layer and was less than 1 nm. Structural properties were investigated using X-ray diffraction (XRD). XRD rocking curves (RC) were obtained in ω-scan mode at (0002) reflection. The minimum value of RC FWHM measured in ω-scan (0002) mode was about 60 arcsec. This value indicates that the layers have high crystalline quality. Specific resistivity of AlN was measured in the temperature range from 300 to 700 K. The values of the specific resistivity for AlN were found to be exceed 4 × 1013 and 1 × 109 Ω cm at 300 and 700 K, respectively.