Atomic layer deposition (ALD) is a key process for making highly uniform and conformal thin films for nano-devices by alternating exposures of a surface to vapors of two (or more) different chemical reactants. In order to realize thin layers of a mono-atomic scale with excellent step coverage, an ALD system has been designed and constructed. Using the constructed ALD system, Ru films have been deposited on 6-in. Si(100) wafers and their characteristics have been studied. Ru(CO)(3)(C6H8) and NH3 were used as reactant gases and Ar was used as a carrier and Purge gas. (c) 2005 Elsevier B.V. All rights reserved.