Barium bis(β-diketonate)·tetraglyme complexes as potential CVD precursors for electronic materials

MOCVD, one preferred technique of the present electronics industry, has not yet emerged as the thin film method of choice for group 2 element containing materials due to the demonstrable shortcomings of the available source compounds. Most specifically, the challenge presented by the group 2 element charge/ionic radius ratio must be overcome to meet the vapor pressure requirements for CVD. To date, development of group 2 precursors suitable for MOCVD has focused mainly on the use of substituted acetylacetonate (acac) complexes. Earlier, several series of somewhat volatile precursors were developed by the use of acetylacetonate complexes containing fluorinated sidegroups. These precursors, while elegantly designed for the thermal deposition of BaF₂, are not ideal for the preparation of oxide thin films. This arises from their propensity to initially form MF₂, which must be reacted further in situ, or in a post-deposition treatment to yield the ultimately sought metal oxide. It is of interest, therefore, to develop stable, volatile precursors lacking fluorinated ligands.