Group 2 element and related compounds as chemical vapour deposition precursors for high‐temperature superconducting metal oxides

Abstract

Abstract The advent of high‐temperature superconducting metal oxides (SMOs) has prompted an increasing number of studies aimed at the development of new routes to their syntheses, in particular in the form of thin films. The preferred method in this regard has been that of chemical vapour deposition (CVD); however, significant difficulties have been associated with the efficacy of commercial precursors for the group 2 metals, in particular those of the bis(β‐diketonates) of barium, whose co‐ordinative unsaturation leads to cluster formation. The development of alternative β‐diketonate precursor systems has focused upon the synthesis of stable Lewis acid‐base complexes by either inter‐ or intramolecular stabilisation. The results of these studies are described herein, along with a review of the research to date on non‐β‐diketonate derivatives of the group 2 metals, including organometallic, halide, amide, carboxylate and alkoxide compounds. On the basis of the results to date, a series of goals for the synthesis of the ideal precursor are discussed.