Some recent developments in the chemical vapour deposition of electroceramic oxides

Metalorganic chemical vapour deposition (MOCVD) and atomic layer deposition (ALD) are highly promising techniques for the deposition of dielectric and ferroelectric oxide thin films, which have a variety of applications in electronic devices. A key requirement for both MOCVD and ALD is the availability of precursors with appropriate physical properties and decomposition characteristics, but there are problems associated with many of the existing precursors. Therefore, it is sometimes necessary to `tailor' the properties of the precursor in order to optimize MOCVD and ALD process parameters, such as evaporation temperature, deposition temperature, layer purity and uniformity. In this paper, the design of a number of new, improved oxide precursors is described, with emphasis on the influence of molecular structure on precursor properties and on the growth dynamics of the MOCVD and ALD processes.