Room-Temperature Epitaxial Growth of High Quality AlN on SiC by Pulsed Sputtering Deposition

Abstract

AlN films have been grown on atomically flat 6H-SiC (0001) C-polarity substrates by pulsed sputtering deposition (PSD) at room temperature (RT). Stepped and terraced structures were clearly observed on the surface of the RT-grown AlN films, which is indicative of the two dimensional growth of AlN films with atomically flat surfaces. The full-width at half-maximum values of the X-ray rocking curves for the AlN 0004 and 1012 diffractions were as low as 150 and 215 arcsec, respectively. X-ray reciprocal space mapping has revealed that the introduction of misfit dislocations in the AlN films is suppressed in the case of RT growth, which is probably the reason behind the improvement in crystalline quality that is achieved by reducing the growth temperature. It has also been found that misfit dislocations were not even introduced by annealing at 1200 °C, indicating that the activation energy for the introduction of dislocations is quite high for the AlN/SiC structure.