Metal-organic chemical vapour deposition of thin films of cobalt on different substrates: study of microstructure

Abstract

We have investigated the microstructure of thin films grown by metal-organic chemical vapour deposition using a β-diketonate complex of cobalt, namely cobalt (II) acetylacetonate. Films were deposited on three different substrates: Si(100), thermally oxidised silicon [SiO₂/Si(100)] and glass at the same time. As-grown films were characterised by X-ray diffraction, scanning electron microscopy, scanning tunnelling microscopy, atomic force microscopy and secondary ion mass spectrometry. Electrical resistivity was measured for all the films as a function of temperature. We found that films have very fine grains, resulting in high electrical resistivity. Further, film microstructure has a strong dependence on the nature of the substrate and there is diffusion of silicon and oxygen into cobalt from the substrate.