In this paper, the effects of thickness of AlN nucleation layer grown at high temperature on AlN epi-layer crystalline quality are investigated. Crack-ftee AlN samples with various nucleation thicknesses are grown on ...In this paper, the effects of thickness of AlN nucleation layer grown at high temperature on AlN epi-layer crystalline quality are investigated. Crack-ftee AlN samples with various nucleation thicknesses are grown on sapphire substrates by plasma-assisted molecular beam epitaxy. The AlN crystalline quality is analysed by transmission electron microscope and x-ray diffraction （XRD） rocking curves in both （002） and （102） planes. The surface profiles of nucleation layer with different thicknesses after in-situ annealing are also analysed by atomic force microscope. A critical nucleation thickness for realising high quality AlN films is found. When the nucleation thickness is above a certain value, the （102） XRD full width at half maximum （FWHM） of AlN bulk increases with nucleation thickness increasing, whereas the （002） XRD FWHM shows an opposite trend. These phenomena can be attributed to the characteristics of nucleation islands and the evolution of crystal grains during AlN main layer growth.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60536020 and 60723002)the National Basic Research Program of China (Grant Nos. 2006CB302800 and 2006CB921106)+1 种基金the National High Technology Research and Development Program for Advanced Materials of China (Grant No. 2006AA03A105)the Major Project of Beijing Municipal Science and Technology Commission,China (Grant No. D0404003040321)
文摘In this paper, the effects of thickness of AlN nucleation layer grown at high temperature on AlN epi-layer crystalline quality are investigated. Crack-ftee AlN samples with various nucleation thicknesses are grown on sapphire substrates by plasma-assisted molecular beam epitaxy. The AlN crystalline quality is analysed by transmission electron microscope and x-ray diffraction （XRD） rocking curves in both （002） and （102） planes. The surface profiles of nucleation layer with different thicknesses after in-situ annealing are also analysed by atomic force microscope. A critical nucleation thickness for realising high quality AlN films is found. When the nucleation thickness is above a certain value, the （102） XRD full width at half maximum （FWHM） of AlN bulk increases with nucleation thickness increasing, whereas the （002） XRD FWHM shows an opposite trend. These phenomena can be attributed to the characteristics of nucleation islands and the evolution of crystal grains during AlN main layer growth.
