Semiconductor device with improved ESD protection

An semiconductor device, comprising:

• a semiconductor substrate with a thickness of less than about 100 micrometers and with a first substrate side and an opposite second substrate side;
• a plurality of monolithically integrated Zener or avalanche diodes with a reverse breakdown voltage of less than about 20 V, which are defined in the semiconductor substrate and which are connected with each other in a series connection,
• wherein the diodes are defined in a plurality of mutually isolated substrate islands in the semiconductor substrate, at least one diode per substrate island, and
• wherein the substrate islands are laterally surrounded by through-substrate isolations extending from the first to the second substrate side and comprising a filling that electrically isolates a respective substrate island from a respective laterally surrounding area of the semiconductor substrate, wherein a first metallization is provided on the first substrate side, and a second metallization is provided on the second substrate side, and wherein the through-substrate isolations comprise an electrically conductive via, which is electrically isolated from the semiconductor substrate by an insulation layer and which provides an electrical pathway between the first and second substrate sides, wherein the substrate islands have a first conductivity type, and the diodes, to form their respective pn junction, comprise a substrate region of an opposite second conductivity type laterally embedded in the substrate island on one substrate side, and wherein diodes in different substrate islands are connected through the first or second metallization and the via.