Patent ID: 8530953

Claim:
A transistor power switch device comprising: a semiconductor body presenting opposite first and second faces; an array of vertical transistor elements for carrying current between said first and second faces, wherein said array of vertical transistor elements comprises at said first face an array of first current carrying transistor regions of a first semiconductor type, at least one second current carrying transistor region of a second semiconductor type opposite to said first type interposed between said first semiconductor regions and said second face, and at least one control electrode for switchably enabling flow of said current through said second transistor region in a forward direction in an on state of the transistor power switch device and switching off said flow of said current in an off state of the transistor power switch device; and a conductive layer contacting said first current carrying transistor regions and insulated from said control electrode by at least one insulating layer; and, at least one vertical avalanche diode in said semiconductor body electrically in parallel with said array of vertical transistor elements arranged so that said avalanche diode as well as said array of vertical transistor elements conduct breakdown avalanche current between said first and second faces in the off state of the transistor power switch device, wherein said vertical avalanche diode is reverse biased in said on state of the transistor power switch device, and said vertical avalanche diode comprises a first current carrying diode region of said second semiconductor type in contact with said first face and with said conductive layer and a second semiconductor region of said first semiconductor type electrically connected with said second face.