Effects of gallium as a surfactant for the growth of AlN epilayers on SiC substrates by metal-organic chemical-vapour deposition were studied. It was found that the use of gallium as a surfactant enabled the growth of thick crack-free AlN epilayers on SiC substrates. The photoluminescence and X-ray diffraction analysis showed that gallium surfactant could reduce some of the tensile strain in AlN epilayers and improved the surface smoothness. X-ray diffraction rocking curves yielded decreased full widths at half maximum for the (105) and (002) reflections, indicating a reduction in threading dislocation density in the AlN epilayers.

Surfactant Effects of Gallium on Quality of AlN Epilayers Grown via Metal-Organic Chemical-Vapour Deposition on SiC Substrates. T.M.Altahtamouni, J.Li, J.Y.Lin, H.X.Jiang: Journal of Physics D, 2012, 45[28], 285103