Highly volatile, low-melting, fluorine-free precursors for MOCVD of lanthanide oxide-containing thin films

The synthesis of a new class of lanthanide ketoiminate-based MOCVD precursors which are fluorine-free, highly volatile, and liquids under typical film growth conditions is presented. The synthesis exploits reactive Ln(NTMS₂)₃ in the high yield, one-pot preparation of analytically pure Ln(miki)₃ complexes. Advantages of this reaction include: the synthetic by-products can be easily removed, the methodology should be applicable to all lanthanide ions, and that the ketoiminate architecture offers a high degree of flexibility for tuning both volatility and melting point. The viability of these precursors for MOCVD has been explicitly demonstrated using Ce(miki)₃ in the growth of high-quality CeO₂ films.