A contact structure (30) in an electronic semiconductor device, including a first conducting region (31) having a first thin portion with a first sublithographic dimension in a first direction; a second conducting region (32) having a second thin portion (32a) with a second sublithographic dimension in a second direction transverse to said first direction; the first and second conducting regions being in direct electrical contact at the first and second thin portions and defining a contact area (33) having a sublithografic extension, lower than 100 nm, preferably about 20 nm. The thin sublithographic portions are obtained using deposition instead of lithography: the first thin portion is deposed on a wall of an opening in a first dielectric layer (34); the second thin portion is obtained by deposing a sacrificial region on vertical wall of a first delimitation layer, deposing a second delimitation layer on the free side of the sacrificial region, removing the sacrificial region to form a sublithographic hard mask opening that is used to etch a mold opening (40) in a mold layer (38) and filling the mold opening.