Amorphous Ru(P) films were grown by chemical vapor deposition (CVD) either using a single source precursor, cis-dihydridotetrakis(trimethylphosphine)Ru (cis-RuH2(P(CH3)3)4), or dual sources, trirutheniumdodecarbonyl (Ru3(CO)12) and trimethylphosphine (P(CH3)3) at 575 K with a cold wall CVD system having a base pressure of 6.7×106 Pa. The impact of atomic percent phosphorus on the microstructure and resistivity has been previously reported. This paper explores the impact of phosphorus loading on conformal film growth, and the adhesion between the amorphous films and copper and between the amorphous films and various substrates. Transmission electron microscopy showed that the Ru(P) films grown with RuH2(P(CH 3)3)4 on 1.0 μ m trench patterns having ∼ 8:1 aspect ratio were fully continuous. An 8 nm thick film grown with the dual sources showed improved step coverage compared to the CVD Ru film grown only with Ru3(CO)12- The changes in step coverage are associated with lower reactivity in the case of RuH2(P(CH 3)3)4 and a lowered sticking coefficient of Ru3(CO)12 in the presence of P(CH3)3 molecules on the Ru surface. Cu wettability on the Ru(P) film surface was examined with low energy ion scattering spectroscopy and X-ray photoelectron spectroscopy. The Ru(P) surface was fully covered with ∼ 0.4 nm thick PVD Cu, indicating comparable Cu wettability of Ru(P) with PVD Ru. Strong adhesion between Ru(P) and Cu films was observed in annealing experiments, which revealed adhesion strength in the order of Ru(P) alloy ≥ Ta ≥ TaN. First principles density functional calculations suggest the metallic properties of the Ru(P) films, and show that the adhesion strength of the Ru/Cu interface is reduced in the presence of phosphorus at the interface.