Properties of AlN epitaxial layers on 6H–SiC substrate grown by sublimation in argon, nitrogen, and their mixtures

Epitaxial layers of aluminum nitride (AlN) have been grown at temperature 1900 °C on 10 mm × 10 mm 6H–SiC substrate via sublimation–recondensation in RF heated graphite furnace. The source material was polycrystalline sintered AlN. Growth of AlN layers in pure nitrogen, mixed nitrogen/argon and pure argon atmosphere of 50 mbar were compared. mum growth rate of about 30 μm/h was achieved in pure nitrogen atmosphere. rface morphology reflects the hexagonal symmetry of the seed, which is characteristic of an epitaxial growth for samples grown in a pure nitrogen and mixed nitrogen/argon atmosphere. X-ray diffraction (XRD) measurements show very strong and well defined (0 0 0 2) reflection positioned at around 36° in symmetric θ–2θ scans. Micro-Raman spectroscopy reveals that the films have a wurtzite structure. ary-ion mass spectroscopy (SIMS) results showed a low concentration of carbon incorporation in the AlN layers. This study demonstrates that nitrogen is necessary for the successful epitaxial growth of AlN on 6H–SiC by sublimation.