Effects of Ⅴ/Ⅲ Ratios on the Properties of A1N Grown on Si (111) Substrate by LP-MOCVD

摘要

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 1100℃, 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.