Growth kinetics and morphology of high quality AlN grown on Si(111) by plasma-assisted molecular beam epitaxy

AlN layers were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. Crystal quality was assessed by atomic force microscopy and high resolution x-ray diffraction. The III/V ratio and the growth temperature, rather than thickness and growth rate, are found to be critical parameters to achieve good quality AlN layers. III/V ratios close to stoichiometry, and high growth temperatures (greater than or equal to 900 degrees C) lead to optimal AlN layers. The growth rate is barely modified when growth temperature changes from 780 to 920 degrees C, but the growth mode and surface roughness are strongly affected. Optimal AlN layers have full-widths at half-maximum values of 10 arcmin, and an average surface roughness of 48 Angstrom. (C) 1997 American Institute of Physics. [S0021-8979(97)07420-3].