Area selective atomic layer deposition of ruthenium with phenol as a small molecule inhibitor

A study on area selective atomic layer deposition (AS-ALD) of ruthenium was performed using phenol as a small molecule inhibitor (SMI). The surfaces studied were native SiO2, Co, Cu, W, TiN, HfO2, and ZrO2. First, all the surfaces were exposed at 350 °C to 200 exposures of a 15 s pulse of phenol followed by 40 s of N2 purging. Ru film was then deposited using bis(cyclopentadienyl)ruthenium (RuCp2) as a precursor and O2 as a coreactant at 350 °C. The surfaces were characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy, and the results show that the extent of the Ru growth inhibition by phenol on the different surfaces depends on their chemical nature. Selective chemisorption of phenol on W, TiN, HfO2, and ZrO2 prevents the Ru film from growing, making them nongrowth surfaces in relation to native SiO2 and Co, which are growth surfaces (GSs). Selectivities of all the GSs are greater than 0.8 with respect to W and TiN up to 1000 Ru ALD cycles and with respect to ZrO2 up to 900 Ru ALD cycles. This work adds another aromatic compound to the toolbox of AS-ALD with SMIs and suggests exploring the potential of other aromatic compounds as SMIs.