High-quality Co films with low resistivity (10 mu Omega cm) were deposited by plasma-enhanced atomic layer deposition (PE-ALD) from metallorganic precursors and NH3 plasma. The deposition characteristics and film properties were investigated. Especially, we compared the results using two cyclopentadienyl Co precursors, CoCp(CO)(2) and CoCp2. While low resistivity Co films were deposited by both precursors, much better self-limiting behavior was observed for CoCp2. Rutherford backscattering and X-ray photoelectron spectroscopy analysis have shown that the impurity contents in PE-ALD Co film were very low. CoSi2 formation by post deposition annealing with Ti capping layer was studied by synchrotron X-ray diffraction. (c) 2006 The Electrochemical Society.