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(η 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 μΩ cm) grew at deposition temperatures between 200 and 300 °C, where the growth per cycle (GPC) during Ru ALD was 0.2 to 0.4 Å cy −1 at 265 °C. The Ru incubation times were considerably shorter using the novel precursor (negligible on Pt and TiN, ∼22 cycles on SiO 2 ) 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 SiO 2 substrates, where a high RuO x content resulted on the SiO 2 substrate. The incubation cycle free ALD Ru film was deposited using an open-coordinated structured Ru( ii ) precursor, Ru(η 5 -cycloheptadienyl) 2 .