Chemical Vapor Deposition of Hafnium Dioxide Thin Films from Cyclopentadienyl Hafnium Compounds

Thin films of HfO2 were grown by metal-organic chemical vapour deposition on fused quartz substrates in the temperature range of 400–500 °C using some bis(cyclopentadienyl)bis(alkoxide)hafnium (IV) precursors, namely Cp2Hf(OiPr)2, [Cp2Hf{OCH(CH3)CH2OCH3}2], [Cp2Hf{OC(CH3)2CH2OCH3}2] and [Cp2Hf{OC(CH2CH3)2CH2OCH3}2]. These complexes, analyzed by nuclear magnetic resonance and thermogravimetric measurements, resulted pure and very stable towards air and moisture. The obtained films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. The deposits contained hafnium and oxygen in the right stoichiometric ratio with a low carbon contamination and they consisted of monoclinic HfO2 phase (baddeleyite) with a granular surface morphology.