High quality aluminum nitride layer grown with a combined step of nitridation and trimethylaluminum preflow

ABSTRACT In this work, aluminum nitride (AlN) layers were grown on sapphire substrate with different times and temperatures of nitridation through metal organics chemical vapor deposition growth technique. Besides, during the growth process, trimethylaluminum (TMAl) preflow was introduced, in particular, after the nucleation. From x-ray diffraction measurement in (002) and (102) reflections, it was found that an average threading dislocation density (TDD) for the AlN layer without nitridation was around 1.07 × 109 cm−2. By applying the nitridation for 20 minutes at 850 oC, the average TDD in the corresponding AlN layer reduced down to ∼9.33 × 108 cm−2. Moreover, the layer exhibited a smoother surface, as observed from atomic force microscopy measurement. Overall, the results from this work suggested that a proper time and temperature of nitridation with the introduction of TMAl preflow could be a promising alternative for obtaining a high quality AlN layer.