Synthesis and Characterization of Tris(β‐ketoiminato)ruthenium(III) Complexes: Potential Precursors for CVD of Ru and RuO₂ Thin Films

The synthesis and characterization of Ru III metal complexes [Ru(keim1) 3 ] ( 1 ) and [Ru(keim2) 3 ] ( 2 ) are reported, where (keim)H is an abbreviation for the fluorinated ketoimine ligands with formula HOC(CF 3 )=CHCR=NMe; (keim1)H with R = Me and (keim2)H with R = CF 3 . These newly synthesized complexes were characterized by spectroscopic methods, while the second complex, 2 , was further examined by single‐crystal X‐ray diffraction (XRD), revealing an octahedral coordination for the Ru cation, with three ketoiminate arranged in a mer ‐configuration, a consequence of the enhanced steric interaction between ligands. Moreover, both Ru metal complexes show good volatility and thermal stability. CVD experiments were conducted using these complexes at temperatures of 325–450 °C. The Ru metal and RuO 2 thin films on silicon wafers were successfully obtained using either a mixture of 2 % O 2 in argon or pure O 2 as the carrier gas, respectively. Our result shows that a 2 % O 2 concentration induces the formation of Ru metal, while that only complex 1 gives formation of a columnar RuO 2 phase upon switching to pure O 2 as the CVD carrier gas. Scanning electron microscopy (SEM) images were taken to reveal surface morphologies, while X‐ray photoelectron spectroscopy (XPS) and XRD were utilized to access their atomic composition as well as the intrinsic packing of the as‐deposited thin film materials.