Bidirectional power semiconductor
A bidirectional power semiconductor device with full turn-off control in both current directions and improved electrical and thermal properties is provided, the device comprises a plurality of first gate commutated thyristor (GCT) cells and a plurality of second GCT cells alternating with each other, a first base layer of each first GCT cell is separated from a neighbouring second anode layer of a neighbouring second GCT cell by a first separation region, and a second base layer of each second GCT cell is separated from a neighbouring first anode layer of a neighbouring first GCT cell by a second separation region.
1. A bidirectional 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 bidirectional power semiconductor device comprising:
at least one first gate commutated thyristor cell and at least one second gate commutated thyristor cell,
wherein each first gate commutated thyristor cell comprises the following layers in the order from the first main side to the second main side:
a first cathode electrode;
a first cathode layer of a first conductivity type;
a first base layer of a second conductivity type different from the first conductivity type;
a first drift layer of the first conductivity type;
a first anode layer of the second conductivity type; and
a first anode electrode,
wherein each first gate commutated thyristor cell further comprises a first gate electrode which is arranged lateral to the first cathode layer and separated from the first cathode layer by the first base layer,
wherein each second gate commutated thyristor cell comprises the following layers in the order from the first main side to the second main side:
a second anode electrode;
a second anode layer of the second conductivity type;
a second drift layer of the first conductivity type;
a second base layer of the second conductivity type;
a second cathode layer of the first conductivity type; and
a second cathode electrode,
wherein each second gate commutated thyristor cell further comprises a second gate electrode which is arranged lateral to the second cathode layer and separated from the second cathode layer by the second base layer, wherein
the bidirectional power semiconductor device comprises at least two first gate commutated thyristor cells and at least two second gate commutated thyristor cells, wherein the first gate commutated thyristor cells alternate with the second gate commutated thyristor cells,
the first base layer of each first gate commutated thyristor cell is separated from a neighboring second anode layer in a second gate commutated thyristor cell by the first drift layer and the second drift layer extending to the surface of the device, thereby forming a first separation region of the first conductivity type between the first base layer and the second anode layer, and
the second base layer of each second gate commutated thyristor cell is separated from a neighbouring first anode layer in a first gate commutated thyristor cell by the first drift layer and the second drift layer extending to the surface of the device, thereby forming a second separation region of the first conductivity type between the second base layer and the first anode layer.
2. The bidirectional power semiconductor device according to claim 1 , wherein for each first gate commutated thyristor cell:
the lateral distance between any point in the first base layer of this first gate commutated thyristor cell and the neighbouring second anode layer is less than a first maximum distance,
the lateral distance between any point of the first anode layer of this first gate commutated thyristor cell and the neighbouring second base layer is less than the first maximum distance,
the first maximum distance is 1 mm.
3. The bidirectional power semiconductor device according to claim 2 , wherein for each second gate commutated thyristor cell:
the lateral distance between any point of the second base layer of this second gate commutated thyristor cell and the neighbouring first anode layer is less than a second maximum distance,
the lateral distance between any point in the second anode layer of this second gate commutated thyristor cell and the neighbouring first base layer is less than the second maximum distance,
the second maximum distance is 1 mm.
4. The bidirectional power semiconductor device according to claim 2 , wherein in a projection in a direction orthogonal to the first and second main side, the first anode layer overlaps with the first cathode layer in each first gate commutated thyristor cell, and the second anode layer overlaps with the second cathode layer in each second gate commutated thyristor cell.
5. The bidirectional power semiconductor device according to claim 2 , wherein for each second gate commutated thyristor cell:
the lateral distance between any point of the second base layer of this second gate commutated thyristor cell and the neighbouring first anode layer is less than a second maximum distance,
the lateral distance between any point in the second anode layer of this second gate commutated thyristor cell and the neighbouring first base layer is less than the second maximum distance,
the second maximum distance is 500 μm.
6. The bidirectional power semiconductor device according to claim 1 , wherein for each second gate commutated thyristor cell:
the lateral distance between any point of the second base layer of this second gate commutated thyristor cell and the neighbouring first anode layer is less than a second maximum distance,
the lateral distance between any point in the second anode layer of this second gate commutated thyristor cell and the neighbouring first base layer is less than the second maximum distance,
the second maximum distance is 1 mm.
7. The bidirectional power semiconductor device of claim 6 , wherein in a projection in a direction orthogonal to the first and second main side, the first anode layer overlaps with the first cathode layer in each first gate commutated thyristor cell, and the second anode layer overlaps with the second cathode layer in each second gate commutated thyristor cell.
8. The bidirectional power semiconductor device according to claim 1 , wherein in a projection in a direction orthogonal to the first and second main side, the first anode layer overlaps with the first cathode layer in each first gate commutated thyristor cell, and the second anode layer overlaps with the second cathode layer in each second gate commutated thyristor cell.
9. The bidirectional power semiconductor device according to claim 8 , wherein in the projection in the direction orthogonal to the first and second main side, the first anode layer is aligned with the first cathode layer to have a maximum overlap between these two layers in each first gate commutated thyristor cell, and the second anode layer is aligned with the second cathode layer to have a maximum overlap between these two layers in each second gate commutated thyristor cell.
10. The bidirectional power semiconductor device according to claim 1 , wherein:
each first gate electrode is formed as part of a first gate metallization layer on the first base layers, the surface of the first gate metallization layer opposite to the first base layers defining a first plane,
each second gate electrode is formed as part of a second gate metallization layer on the second base layers, the surface of the second gate metallization layer opposite to the second base layers defining a second plane,
the surfaces of the first cathode electrodes opposite to the first cathode layers and the surfaces of the second anode electrodes opposite to the second anode layers define a third plane,
the surfaces of the first anode electrodes opposite to the first anode layers and the surfaces of the second cathode electrodes opposite to the second cathode layers define a fourth plane,
the first plane is parallel to the third plane and is shifted from the third plane in a direction from the first main side to the second main side, and
the second plane is parallel to the fourth plane and is shifted from the fourth plane in a direction from the second main side to the first main side.
11. The bidirectional power semiconductor device according to claim 1 , wherein each one of the first and second cathode layers includes at least two cathode layer regions, which are separated from each other by the first or second base layer.
12. The bidirectional power semiconductor device according to claim 11 , wherein each one of the cathode layer regions, is strip-shaped with a length in the longitudinal axis and a width in a direction vertical to the longitudinal axis, wherein the width is less than the length.
13. The bidirectional power semiconductor device according to claim 12 , wherein each one of the first and second cathode layers comprises 2 to 6 strip-shaped cathode layer regions.
14. The bidirectional power semiconductor device according to claim 12 wherein the width of each strip-shaped cathode semiconductor layer region is between 50 μm and 500 μm.
15. The bidirectional power semiconductor device according to claim 12 , wherein the strip-shaped cathode layer regions are placed in concentric rings around the center of the device, the longitudinal axis of each strip extending along a radial direction which is a direction extending from the center of the device and parallel to the first and second main side.
16. The bidirectional power semiconductor device according to claim 1 , wherein the ratio between a lateral width of the first base layer and that of the first anode layer and the ratio between a lateral width of the second base layer and that of the second anode layer are between 0.5 and 2, respectively.
17. The bidirectional power semiconductor device according to claim 1 , wherein the first and second drift layers of the first and second gate commutated thyristor cells form one continuous semiconductor layer extending parallel to and between the first and second main side of the wafer.
18. The bidirectional power semiconductor device according to claim 1 , wherein the first and the second base layers have a greater thickness in a direction orthogonal to the first and second main side than the first and second anode layers.
19. The bidirectional power semiconductor device according to claim 1 , wherein the distance between each pair of neighbouring first base layer and second anode layer and the distance between each pair of neighbouring second base layer and first anode layer is in a range between 20 μm and 100 μm.
20. The bidirectional power semiconductor device according to claim 1 , wherein for each first gate commutated thyristor cell:
the lateral distance between any point in the first base layer of this first gate commutated thyristor cell and the neighbouring second anode layer is less than a first maximum distance,
the lateral distance between any point of the first anode layer of this first gate commutated thyristor cell and the neighbouring second base layer is less than the first maximum distance,
the first maximum distance is 500 μm.