Epitaxial growth of $Co_3O_4$ films by low temperature, low pressure chemical vapor deposition

Abstract

The growth of strongly oriented or epitaxial thin films of metal oxides generally requires relatively high growth temperatures or infusion of energy to the growth surface through means such as ion bombardment. We have grown high quality epitaxial thin films of $Co_3O_4$ on different substrates at a temperature as low as 450° C by low pressure metal organic chemical vapor deposition (MOCVD) using cobalt(II) acetylacetonate as the precursor. With oxygen as the reactant gas, polycrystalline $Co_3O_4$ films are formed on glass and Si(100) in the temperature range 350 550° C. Under similar conditions of growth, highly oriented films of $Co_3O_4$ are formed on $SrTiO_3(100)$ and $LaAlO_3(100)$. The film on $LaAlO_3(100)$ grown at 450° C show a rocking curve FWHM of 1.61°, which reduces to 1.32° when it is annealed in oxygen at 725° C. The film on $SrTiO_3(100)$ has a FWHM of 0.33° (as deposited) and 0.29° (after annealing at 725° C). The φ-scan analysis shows cube on cube epitaxy on both these substrates. The quality of epitaxy on $SrTiO_3$ (100) is comparable to the best of the perovskite basedoxide thin films grown at significantly higher temperature