An integrated device having: a first conductive region; a second conductive region; an insulating layer arranged between the first and the second conductive region; at least one through opening extending in the insulating layer between the first and the second conductive region; and a contact structure formed in the through opening and electrically connecting the first conductive region and the second conductive region. The contact structure is formed by a conductive material layer that coats the side surface and the bottom of the through opening and surrounds an empty region which is closed at the top by the second conductive region. The conductive material layer preferably comprises a titanium layer and a titanium-nitride layer arranged on top of one another.