Low Temperature Atomic Layer Deposition of Ruthenium Thin Films Using Isopropylmethylbenzene-Cyclohexadiene-Ruthenium and O[sub 2]

Abstract

Ru thin films were deposited by atomic layer deposition (ALD) through alternating exposures of a metallorganic precursor, C16H22Ru [(eta 6-1-isopropyl-4-methylbenzene) (eta 4-cyclohexa-1,3-diene)ruthenium(0)] and O-2 at 220 degrees C. The growth rate was 0.1 and 0.086 nm/cycle on TiN and thermally grown SiO2, respectively. On both substrates, negligible incubation cycles were observed indicating that Ru nucleation was enhanced compared to the results obtained using the cyclopentadienyl-based Ru precursors. Plan-view transmission electron microscopy analysis revealed the formation of a continuous Ru film with a thickness of similar to 3.5 nm after only 50 ALD cycles. The step coverage was approximately 100% over the contact holes (top opening diameter was 89 nm) with a high aspect ratio (24:1).