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

• Published in: Thin solid films 2021-10, Vol.736, p.138915, Article 138915
• Main Authors: Yusuf, Y., Samsudin, M.E.A., Md. Sahar, M.A.A.Z., Hassan, Z., Maryam, W., Zainal, N.
• Format: Article
• Language: English
• Subjects: Dislocations; Nitridation temperature; Nitridation time; Surface roughness
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2021.138915

•Combined nitridation step and TMAl preflow improved AlN growth.•The optimum AlN growth was by applying nitridation for 20 minutes at 850 ºC.•Prolonged nitridation established the unwanted N-polar growth.•Higher nitridation temperature destroyed the AlON layer. 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.