Article ID Journal Published Year Pages File Type
1791475 Journal of Crystal Growth 2012 4 Pages PDF
Abstract

AlN layers were grown on (0001) sapphire substrates by hydride vapor phase epitaxy (HVPE) at 1100 °C with a source gas supply sequence of (1) NH3 preflow or (2) AlCl3 preflow. An Al-polarity AlN layer without inclusion of a N-polarity region was grown when AlCl3 was preflown to the sapphire surface prior to AlN growth, while N- and Al-polarity regions were both present in the same AlN layer when NH3 was preflown, since growth was performed on a nitrided sapphire surface. Compared with the AlN layers grown with NH3 preflow, the Al-polarity AlN layers grown with AlCl3 preflow had improved crystalline structural quality, a low concentration of oxygen impurity, and a photoabsorption edge energy of 6.08 eV, which is close to an ideal value. Therefore, the source gas supply sequence has a significant influence on the growth of AlN layers on (0001) sapphire substrates. Thus, preflow of AlCl3 gas to a sapphire surface prior to AlN growth is a key process for high crystalline quality AlN layer growth with uniform Al-polarity on (0001) sapphire substrates by HVPE.

► When AlN is grown with NH3 preflow, both N- and Al-polarity AlN regions are present. ► When AlN is grown with AlCl3 preflow, Al-polarity AlN without incorporation of N-polarity regions can be grown. ► The AlN layer grown with AlCl3 preflow had higher crystalline quality than NH3 preflow. ► AlCl3 preflow prior to HVPE growth of AlN is quite effective for growing high-quality AlN layers on (0001) sapphire substrates.

Related Topics
Physical Sciences and Engineering Physics and Astronomy Condensed Matter Physics
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