Atomic layer deposition of Ru from CpRu(CO)2Et using O2 gas and O2 plasma

The metalorganic precursor cyclopentadienylethyl(dicarbonyl)ruthenium (CpRu(CO)2Et) was used to develop an atomic layer deposition (ALD) process for ruthenium. O2 gas and O2 plasma were employed as reactants. For both processes, thermal and plasma-assisted ALD, a relatively high growth-per-cycle of ∼1 A was obtained. The Ru films were dense and polycrystalline, regardless of the reactant, yielding a resistivity of ∼16 μΩ cm. The O2 plasma not only enhanced the Ru nucleation on the TiN substrates but also led to an increased roughness compared to thermal ALD.