Effects of V/III Ratios on the Properties of AlN Grown on Si (111) Substrate by LP-MOCVD

The AlN thin films were deposited on Si(111) substrates by home-made low pressure metalorganic chemical vapor deposition (LP-MOCVD). At the growth temperature of 1100degC, the effects of the different V/III ratios on the surface morphology and structural characteristics of AlN films were systematically studied. The growth rate of about 150 nm/h was determined by the cross-sectional SEM. By the help of X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements, the obvious effects of the specific growth conditions (different V/III ratios) on the surface morphology and crystallinity of the deposited AlN films were investigated. At the V/III ratio of 15000, the preferred (0002) orientated AlN epitaxial film with the relatively smaller RMS roughness (1.422 nm) was obtained. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical composition and the chemical bonding structure of the AlN film, indicating some Si atoms outdiffusion from the Si substrate occurred