High-Quality Cobalt Thin Films by Plasma-Enhanced Atomic Layer Deposition

High-quality Co films with low resistivity ( 10 μ Ω cm ) were deposited by plasma-enhanced atomic layer deposition (PE-ALD) from metallorganic precursors and NH 3 plasma. The deposition characteristics and film properties were investigated. Especially, we compared the results using two cyclopentadienyl Co precursors, CoCp ( CO ) 2 and CoCp 2 . While low resistivity Co films were deposited by both precursors, much better self-limiting behavior was observed for CoCp 2 . Rutherford backscattering and X-ray photoelectron spectroscopy analysis have shown that the impurity contents in PE-ALD Co film were very low. CoSi 2 formation by post deposition annealing with Ti capping layer was studied by synchrotron X-ray diffraction.