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

Abstract

New Zr, Hf and Y 2,7,7-trimethyl-3,5-octanedionates (tod) as well as the corresponding Cu β-diketonate have been synthesized and characterized by FT-IR, elemental analyses, TGA, and ¹H NMR or ESR. The molecular structure of Hf(tod)₄ has been determined by single-crystal X-ray diffraction, the metal displays a square antiprismatic geometry. Zr, Hf and Y β-diketonates were investigated as precursors for MOCVD deposition of ZrO₂, HfO₂ and yttria-stabilized hafnia thin films. The films were characterized 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.