A semiconductor portion of a semiconductor device includes a semiconductor layer with a drift zone of a first conductivity type and at least one impurity zone of a second, opposite conductivity type. The impurity zone adjoins a first surface of the semiconductor portion in an element area. A connection layer directly adjoins the semiconductor layer opposite to the first surface. At a distance to the first surface an overcompensation zone is formed in an edge area that surrounds the element area. The overcompensation zone and the connection layer have opposite conductivity types. In a direction vertical to the first surface, a portion of the drift zone is arranged between the first surface and the overcompensation zone. In case of locally high current densities, the overcompensation zone injects charge carriers into the semiconductor layer that locally counter a further increase of electric field strength and reduce the risk of avalanche breakdown.