Metal-Organic Atomic Layer Deposition of Metals for Applications in Interconnect Technology

Metal-organic atomic layer deposition (ALD) of ruthenium has been investigated by both thermal and remote plasma-enhanced methods. Based on the metal-organic ruthenium source bis(2,4-dimethylpentadienyl)ruthenium, a suitable reduction path towards the formation of ruthenium films by ALD was found using either molecular oxygen, or a remote nitrogen plasma. The ruthenium films were deposited in-situ on ultra-thin tantalum nitride layers, grown by plasma-enhanced ALD. Although in both the thermal and remote plasma-enhanced ALD cases highly pure ruthenium was obtained, key differences in film growth rate and film surface morphology were identified when comparing both ALD methods