Semiconductor device including ruthenium electrode and method for fabricating the same

A semiconductor device includes a semiconductor substrate, an insulation pattern on the semiconductor substrate, and an etch stop layer on the insulating pattern, the insulation pattern and the etch stop layer defining a contact hole that exposes the substrate, a first plug filled in a portion of the contact hole, a diffusion barrier layer formed above the first plug and in a bottom portion and on sidewalls of a remaining portion of the contact hole, a second plug fainted on the diffusion barrier layer and filled in the contact hole, and a storage node coupled to and formed on the second plug.