Morphology analysis of nickel thin films grown by MOCVD

Abstract

Nickel films on quartz substrates were prepared by metal-organic chemical vapor deposition (MOCVD), from the precursor bis(dimethylglyoximato)Ni(II), [Ni(dmg) 2]. The deposition was carried out at reduced pressure in a horizontal quartz glass reactor. The samples were analysed by profilometry, X-ray diffraction, electron spectroscopy for chemical analysis, atomic force microscopy (AFM) and scanning electron microscopy. Resistances were determined by four-point resistivity measurements. The film microstructure was described by a simplified two-layer model using the data obtained from AFM, profilometry and resistivity measurements. In this model, the films consist of a compact layer (density ≈ 100%) between the substrate and the surface layer and a porous surface layer (density < 100%). Increasing the substrate temperature resulted in an increase in the porous surface layer thickness which can be explained by the growth of separated grains rather than continuous film growth. The grains were thus poorly connected and the resistance increased with an increase in deposition temperature. Metallic films were obtained between 350 and 580°C.