Abstract: A semiconductor device comprises semiconductor substrate including vertical transistor and with dopants of a first type. Each transistor cell of transistor has body region formed in substrate and with dopants of second type. The body regions form first pn-junctions with substrate. A first well region is formed in substrate and with dopants of a second type forming a second pn-junction with substrate. Switch connects this first well region to body regions. A second well region is formed in the substrate and with dopants of a second type to form third pn-junction with substrate. Detection circuit is integrated in the second well region and to detect whether the first pn-junctions are reverse biased. The switch connects or disconnects the first well region(s) and the body regions of the transistor cell, and is opened, when the first pn-junctions are reverse biased, and closed, when the first pn-junctions are not reverse biased.

Abstract: A semiconductor device comprises semiconductor substrate including vertical transistor and with dopants of a first type. Each transistor cell of transistor has body region formed in substrate and with dopants of second type. The body regions form first pn-junctions with substrate. A first well region is formed in substrate and with dopants of a second type forming a second pn-junction with substrate. Switch connects this first well region to body regions. A second well region is formed in the substrate and with dopants of a second type to form third pn-junction with substrate. Detection circuit is integrated in the second well region and to detect whether the first pn-junctions are reverse biased. The switch connects or disconnects the first well region(s) and the body regions of the transistor cell, and is opened, when the first pn-junctions are reverse biased, and dosed, when the first pn-junctions are not reverse biased.