Zr(IV) and Hf(IV) β-diketonate complexes as precursors for the photochemical deposition of ZrO2 and HfO2 thin films

In this paper amorphous ZrO2 and HfO2 thin films were obtained by direct UV irradiation of Zr(IV) and Hf(IV) β-diketonate precursor complexes on Si(1 0 0) and fused silica substrates. The precursors, Zr(CH3COCHCOCH3)4 and Hf(C6H5COCHCOCH3)4 were deposited as amorphous thin films by spin coating. The photochemistry of these films was monitored by FT-IR spectroscopy. The photolysis with 254 nm light led to the loss of the ligands from the coordination complexes, and the production of metallic oxides. The thin films products were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). These analyses revealed that as-deposited films are amorphous and that the presence of carbon is thought to arise from the ligands. However, post-annealing of the photodeposited films favors the stoichiometric and optical properties of ZrO2 and HfO2 thin films.