A reverse-conducting power semiconductor device with a wafer having a first main side and a second main side, which is arranged parallel to the first main side, the device comprising a plurality of diode cells and a plurality of GCT cells, wherein each GCT cell comprises layers in the following order between the first and second main side (11, 15): - a thyristor cathode electrode, - a thyristor cathode layer of a first conductivity type, - a thyristor base layer of a second conductivity type different from the first conductivity type, - a drift layer of the first conductivity type, - a thyristor buffer layer of the first conductivity type, - a thyristor anode layer of the second conductivity type, - a thyristor anode electrode, wherein each GCT cell further comprises a gate electrode, which is arranged lateral to the thyristor cathode layer and separated from the thyristor cathode layer by the thyristor base layer, wherein each diode cell comprises a diode anode electrode on the first main side, a diode anode layer of the second conductivity type, which is separated from the thyristor base layer by the drift layer, the drift layer, a diode cathode layer of the first conductivity type, which is arranged alternating to the thyristor anode layer on the second main side, and a diode cathode electrode, and wherein the device comprises at least one mixed part, in which the diode anode layers of the diode cells alternate with the first cathode layers of the GCT cells, characterized in, that in at least one diode cell a diode buffer layer of the first conductivity type is arranged between the diode anode layer and the drift layer such that the diode buffer layer covers lateral sides of the diode anode layer from the first main side at least to a depth of 90 % of the thickness of the diode anode layer. - a thyristor cathode electrode, - a thyristor cathode layer of a first conductivity type, - a thyristor base layer of a second conductivity type different from the first conductivity type, - a drift layer of the first conductivity type, - a thyristor buffer layer of the first conductivity type, - a thyristor anode layer of the second conductivity type, - a thyristor anode electrode, wherein each GCT cell further comprises a gate electrode, which is arranged lateral to the thyristor cathode layer and separated from the thyristor cathode layer by the thyristor base layer, wherein each diode cell comprises a diode anode electrode on the first main side, a diode anode layer of the second conductivity type, which is separated from the thyristor base layer by the drift layer, the drift layer, a diode cathode layer of the first conductivity type, which is arranged alternating to the thyristor anode layer on the second main side, and a diode cathode electrode, and wherein the device comprises at least one mixed part, in which the diode anode layers of the diode cells alternate with the first cathode layers of the GCT cells, characterized in, that in at least one diode cell a diode buffer layer of the first conductivity type is arranged between the diode anode layer and the drift layer such that the diode buffer layer covers lateral sides of the diode anode layer from the first main side at least to a depth of 90 % of the thickness of the diode anode layer.