Hafnium carbamates and ureates: New class of precursors for low-temperature growth of HfO₂ thin films

Novel volatile compounds of hafnium, namely tetrakis-N,O-dialkylcarbamato hafnium(iv) [Hf(ⁱPrNC(O)OⁱPr)₄] (1) and tetrakis-N,N,N'-trialkylureato hafnium(iv) [Hf(ⁱPrNC(O)N-(Me)Et) ₄] (2), have been synthesized through the simple insertion reaction of isopropyl isocyanate into hafnium isopropoxide and hafnium ethylmethylamide, respectively; based on the promising thermal properties, compound 1 has been evaluated as a precursor for metalorganic chemical vapor deposition (MOCVD) of HfO₂ thin films, which resulted in the growth of stoichiometric and crystalline layers with a uniform morphology at temperature as low as 250 °C.