A vertical semiconductor device includes a semiconductor body having a backside and extending, in a peripheral area and in a vertical direction substantially perpendicular to the backside, from the backside to a first surface of the semiconductor body, the body including in an active area spaced apart semiconductor mesas extending, in the vertical direction, from the first surface to a main surface arranged above the first surface, in a vertical cross-section the peripheral area extending between the active area and an edge that extends between the back-side and the first surface, in the vertical cross-section each of the mesas including first and second side walls, a first pn-junction extending between the first and second side walls, and a conductive region in Ohmic contact with the mesa and extending from the main surface into the mesa. Gate electrodes are arranged between adjacent mesas and extend across the first pn-junctions.