A method and an apparatus of fabricating a metal interconnection in a contact hole of a semiconductor device reduces contact resistance and improves step coverage. A contact hole is opened in an interlayer insulating film formed on a semiconductor substrate. A conductive layer used as an ohmic contact layer is formed on the interlayer insulating film including the contact hole. An upper surface of the conductive layer is nitrided to form a protective layer. An ALD (atomic layer deposition)-metal barrier layer is formed on the protective layer. The resulting metal barrier layer has good step coverage and no impurities, and the protective layer prevents defects in the conductive layer caused by precursor impurities used during the formation of the metal barrier layer.