Patent ID: 11967638
Assignee: HITACHI ENERGY LTD
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A power diode comprising an anode electrode layer, a cathode electrode layer and a plurality of diode cells arranged between the anode electrode layer and the cathode electrode layer, wherein each diode cell comprises:
a first anode layer of a first conductivity type in direct contact with the anode electrode layer, extending in a horizontal direction along an entire portion of the anode electrode layer, and extending in a vertical direction from the anode electrode layer to a first depth, the vertical direction being defined as a direction from the anode electrode layer to the cathode electrode layer and the horizontal direction substantially orthogonal to the vertical direction;
a second anode layer of the first conductivity type having a lower doping concentration than the first anode layer and being separated from the entire portion of the anode electrode layer by the first anode layer, the second anode layer extending in the vertical direction from the first anode layer to a second depth that is larger than the first depth;
a drift layer of a second conductivity type forming a pn-junction with the second anode layer, wherein the second conductivity type is different from the first conductivity type and wherein a horizontal cross-section through each diode cell along a horizontal plane perpendicular to the vertical direction at a third depth comprises, in each diode cell, a first area where the horizontal plane intersects the second anode layer and a second area where the horizontal plane intersects the drift layer, the first depth being smaller than the third depth and the third depth being smaller than the second depth and wherein, in a vertical cross-section perpendicular to the horizontal plane, the second anode layers of each pair of neighboring diode cells are laterally separated from each other by the drift layers of that pair of neighboring diode cells;
a cathode layer of second conductivity type in direct contact with the cathode electrode layer, the cathode layer having a higher doping concentration than the drift layer; and
a cathode-side segmentation layer in direct contact with the cathode electrode layer, wherein a material of the cathode-side segmentation layer is an insulating material or a lightly doped semiconductor of the first conductivity type having an integrated doping content along a direction perpendicular to a main side that is below 2·1013 cm−2.