New sterically hindered Hf, Zr and Y β-diketonates as MOCVD precursors for oxide films

New Zr, Hf and Y 2,7,7-trimethyl-3,5-octanedionates (tod) as well as the corresponding Cu beta-diketonate were synthesised and characterised by FT-IR, elemental analyses, TGA, and 1H NMR or ESR. The molecular structure of Hf(tod)4 was determined by single-crystal XRD. The metal displays a square antiprismatic geometry. Zr, Hf and Y beta-diketonates were investigated as precursors for MOCVD deposition of ZrO2, HfO2 and yttria-stabilised hafnia thin films. The films were characterised by XRD, XPS, EDS and AFM. Highly textured and in-plane oriented films were deposited on sapphire by pulsed liquid injection MOCVD. Zr(tod)4 and Hf(tod)4 precursors lead to higher growth rates of ZrO2 and HfO2 films at lower temperatures than conventional Zr(thd)4 and Hf(thd)4 precursors (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) and are attractive new precursors for oxide films. 37 refs.