Synthesis and characterization of hafnium tert-butylacetoacetate as new MOCVD precursor for HfO2 films

A new hafnium β-ketoesterate Hf(tbob)4 (tbob=tert-butyl-3-oxobutanoate or tert-butylacetoacetate) was obtained by ligand exchange reaction applied to Hf2(OiPr)8(iPrOH)2. It was characterized by elemental analysis, FT-IR, 1H NMR, mass-spectroscopy and TGA. The compound is volatile and it was tested for the growth of HfO2 films on Si(100) and R-plane sapphire substrates at 600-800 °C by pulsed liquid injection MOCVD. The films were characterized by XRD, XPS and AFM. Stoichiometric amorphous films were obtained on silicon, while those on sapphire were relatively well crystallized (00l) monoclinic. The growth was kinetically limited in all the temperature range studied (600-800°C).