Atomic Layer Deposition Of A Ruthenium Thin Film Using A Precursor With Enhanced Reactivity

Ruthenium (Ru) thin films were grown via atomic layer deposition (ALD) using a novel Ru precursor with enhanced reactivity, namely Ru(eta(5)-cycloheptadienyl)(2) (Ru(chd)(2)) and O-2. Self-limiting growth during the Ru ALD process was achieved by varying the Ru precursor and O-2 feeding times. Metallic Ru films with a low resistivity (10-16 mu Omega cm) grew at deposition temperatures between 200 and 300 degrees C, where the growth per cycle (GPC) during Ru ALD was 0.2 to 0.4 angstrom cy(-1) at 265 degrees C. The Ru incubation times were considerably shorter using the novel precursor (negligible on Pt and TiN, similar to 22 cycles on SiO2) compared with those associated with Ru ALD using a high-valency Ru precursor and O-2. The characteristics of the Ru film were influenced by the substrate. Specifically, the Pt substrate gave rise to an amorphous film, while crystalline films were grown on the TiN and SiO2 substrates, where a high RuOx content resulted on the SiO2 substrate.