Abstract: The aim of this paper is to examine the effects of TMAl preflow on the properties of AlN epitaxial layer grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD) using high-temperature treatments.The entire epitaxial growth process was monitored by in situ Epitt.At the same time, the surface morphology and crystal quality of AlN epitaxial layer were studied.The results show that TMAl preflow leads to the decrease of the crystal quality of the AlN epitaxial layer, and it also has a significant effect on the strain.

Key words: The aim of this paper is to examine the effects of TMAl preflow on the properties of AlN epitaxial layer grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD) using high-temperature treatments.The entire epitaxial growth process was monitored by in situ Epitt.At the same time, the surface morphology and crystal quality of AlN epitaxial layer were studied.The results show that TMAl preflow leads to the decrease of the crystal quality of the AlN epitaxial layer, and it also has a significant effect on the strain.