Atomic Layer Deposition of Ruthenium and Ruthenium-oxide Thin Films by Using a Ru(EtCp)2 Precursor and Oxygen Gas

In this study, the growth characteristics and the film properties of Ru and RuO2 thin films were systematically investigated, focusing on the effects of the oxygen exposure and the growth temperature. Pure Ru thin films with low resistivity were deposited from bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)(2)] as a Ru precursor and oxygen (O-2) as a reactant by using thermal atomic layer deposition (ALD). Phase change from Ru to RuO2 was observed by controlling the growth parameters, including the O-2 flow rate and the growth temperature. In order to investigate the dependence of the phase change on the deposition parameters, we evaluated the crystalline structure and the chemical composition by using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).