Epitaxial growth of AlN films on Si (111)

Plasma assisted molecular beam epitaxial growth of AlN on Si(111) at various substrate temperatures with the same III-V ratio is investigated. The epitaxial structures were characterized by high resolution X-ray diffraction (HR-XRD), scanning electrical microscopy (SEM) and atomic force microscopy (AFM). With the increase of the growth temperature, the full-width at half-maximum (FWHM) of the AlN (0002) reflection peak in HR-XRD rocking curve measurements decreases from 5898.5 arcsec for films grown at 575 °C to 1784.9 arcsec for films grown at 900 °C, respectively. AFM images show that the surface roughness decreases with increasing growth temperatures. Though the AlN films are grown with same III-V ratio, the AlN films grown at 575 °C shows nitrogen rich feature and the ones grown at higher temperatures show the metal rich features. The presence of the film morphology can be explained by al mobility.