A device with through-silicon via (TSV) and a method of forming the same includes the formation of an opening in a silicon substrate, the formation of a first insulation layer on the sidewalls and bottom of the opening, the formation of a second insulation layer on the sidewalls and bottom of the opening. A first interface between the first insulation layer and the silicon substrate has an interface roughness with a peak-to-valley height less than 5 nm. A second interface between the second insulation layer and the conductive layer has an interface roughness with a peak-to-valley height less than 5 nm.