Synthesis and characterization of tris(\u3b2-ketoiminato)ruthenium(III) complexes: potential precursors for CVD of Ru and RuO2 thin films

The synthesis and characterization of RuIII 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(CF3)=CHCR=NMe; (keim1)H with R?=?Me and (keim2)H with R?=?CF3. 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 RuO2 thin films on silicon wafers were successfully obtained using either a mixture of 2?% O2 in argon or pure O2 as the carrier gas, respectively. Our result shows that a 2?% O2 concentration induces the formation of Ru metal, while that only complex 1 gives formation of a columnar RuO2 phase upon switching to pure O2 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.NRC publication: Ye