Semiconductor device, RC-IGBT, and method of manufacturing semiconductor device
According to one embodiment, a semiconductor device 100 includes a semiconductor substrate 1 including a first principal surface and a second principal surface, an emitter electrode 46 , a gate wiring 49 , a collector electrode 43 , a first unit cell region 10 that is extended along one direction in a plane parallel to the first principal surface, and a second unit cell region 20 that is extended along one direction, in which the semiconductor substrate 1 of the first unit cell region 10 and the second unit cell region 20 includes an N− type drift layer 39 , an N type hole barrier layer 38 , a trench electrode 13 , a P type body layer 36 , an insulating film 35 , an N type field stop layer 41 , and a P+ type collector layer 42 , and the second unit cell region 20 includes an N type cathode layer 47 that is fitted into the collector layer 42 and is extended along one direction.
1. A semiconductor device comprising:
a semiconductor substrate including a first principal surface and a second principal surface;
an emitter electrode and a gate wiring provided in the first principal surface;
a collector electrode provided in the second principal surface; and
a first unit cell region that is extended along one direction in a plane parallel to the first principal surface and a second unit cell region that is extended in the one direction when they are seen from the side of the first principal surface, wherein
the semiconductor substrate of the first unit cell region and the second unit cell region comprises:
a drift layer of a first conductive type;
a hole barrier layer of a first conductive type that is provided to be closer to the first principal surface than the drift layer is and is extended in the one direction;
a pair of trench electrodes that are provided in such a way as to sandwich the hole barrier layer from both sides thereof in another direction perpendicular to the one direction and are extended in the one direction;
a body layer of a second conductive type that is provided to be closer to the first principal surface than the hole barrier layer is, is extended in the one direction, and is connected to the emitter electrode;
an insulating film that is provided between the trench electrode, and the drift layer, the hole barrier layer, and the body layer;
a field stop layer of a first conductive type provided to be closer to the second principal surface than the drift layer is; and
a collector layer of a second conductive type that is provided to be closer to the second principal surface than the field stop layer is and is connected to the collector electrode,
the trench electrode of the first unit cell region is connected to the gate wiring,
the trench electrode of the second unit cell region is connected to the emitter electrode, and
the semiconductor substrate of the second unit cell region includes a cathode layer of a first conductive type that is fitted into the collector layer, extended in the one direction, and connects the collector electrode and the field stop layer.
2. The semiconductor device according to claim 1 , wherein the cathode layer is provided along a line that passes the center of the second unit cell region in the other direction.
3. The semiconductor device according to claim 1 , wherein the length of the cathode layer in the other direction is smaller than the length of the hole barrier layer in the other direction in the second unit cell region.
4. The semiconductor device according to claim 1 , wherein when the trench electrodes in the second unit cell region are projected in a direction from the first principal surface toward the second principal surface, the cathode layer is formed in a region surrounded by the trench electrodes projected onto the collector layer.
5. The semiconductor device according to claim 1 , wherein
a plurality of the first unit cell regions and a plurality of the second unit cell regions are alternately provided in the other direction, and
the second unit cell regions comprise:
the second unit cell region in which the cathode layer is provided; and
the second unit cell region in which the cathode layer is not provided.
6. The semiconductor device according to claim 1 , further comprising an emitter layer of a first conductive type provided between the trench electrodes of the first unit cell region, the emitter layer being provided to be closer to the first principal surface than the body layer is,
wherein the insulating film is also provided between the emitter layer and the trench electrode.
7. The semiconductor device according to claim 1 , further comprising a floating layer of a second conductive type that is provided to be closer to the first principal surface than the drift layer is and is extended in the one direction, wherein
the body layer is also provided to be closer to the first principal surface than the floating layer is,
the trench electrode is provided between the hole barrier layer and the body layer, and the floating layer, and
the insulating film is provided between the trench electrode and the floating layer.
8. The semiconductor device according to claim 7 , wherein the lower end of the floating layer is closer to the second principal surface than the lower end of the trench electrode is.
9. The semiconductor device according to claim 1 , further comprising an inter-layer insulating film provided on the body layer,
wherein the emitter electrode is contacted to the body layer via a contact groove, the contact groove being provided in such a way as to extend in the one direction, penetrate through the inter-layer insulating film, and reach the body layer.
10. The semiconductor device according to claim 9 , further comprising:
a latch-up prevention layer of a second conductive layer provided below the contact groove; and
a body contact layer of a second conductive type provided between the emitter electrode and the latch-up prevention layer.
11. The semiconductor device according to claim 1 , wherein the length of the first unit cell region in the other direction is substantially equal to the length of the second unit cell region when seen from the direction perpendicular to the first principal surface.
12. An RC-IGBT comprising:
a semiconductor substrate including a first principal surface and a second principal surface;
an emitter electrode and a gate wiring provided in the first principal surface;
a collector electrode provided in the second principal surface; and
a first unit cell region that is extended along one direction in a plane parallel to the first principal surface and a second unit cell region that is extended in the one direction when they are seen from the side of the first principal surface, wherein
the semiconductor substrate of the first unit cell region and the second unit cell region comprises:
a drift layer of a first conductive type;
a hole barrier layer of a first conductive type that is provided to be closer to the first principal surface than the drift layer is and is extended in the one direction;
a pair of trench electrodes that are provided in such a way as to sandwich the hole barrier layer from both sides thereof in another direction perpendicular to the one direction and are extended in the one direction;
a body layer of a second conductive type that is provided to be closer to the first principal surface than the hole barrier layer is, is extended in the one direction, and is connected to the emitter electrode;
an insulating film that is provided between the trench electrode, and the drift layer, the hole barrier layer, and the body layer;
a field stop layer of a first conductive type provided to be closer to the second principal surface than the drift layer is; and
a collector layer of a second conductive type that is provided to be closer to the second principal surface than the field stop layer is and is connected to the collector electrode,
the trench electrode of the first unit cell region is connected to the gate wiring,
the trench electrode of the second unit cell region is connected to the emitter electrode, and
the semiconductor substrate of the second unit cell region includes a cathode layer of a first conductive type that is fitted into the collector layer, extended in the one direction, and connects the collector electrode and the field stop layer.
13. The RC-IGBT according to claim 12 , wherein the cathode layer is provided along a line that passes the center of the second unit cell region in the other direction.
14. The RC-IGBT according to claim 12 , wherein the length of the cathode layer in the other direction is smaller than the length of the hole barrier layer in the other direction in the second unit cell region.
15. The RC-IGBT according to claim 12 , wherein when the trench electrodes in the second unit cell region are projected in a direction from the first principal surface toward the second principal surface, the cathode layer is formed in a region surrounded by the trench electrodes projected onto the collector layer.
16. The RC-IGBT according to claim 12 , wherein
a plurality of the first unit cell regions and a plurality of the second unit cell regions are alternately provided in the other direction, and
the second unit cell regions comprise:
the second unit cell region in which the cathode layer is provided; and
the second unit cell region in which the cathode layer is not provided.
17. The RC-IGBT according to claim 12 , further comprising an emitter layer of a first conductive type provided between the trench electrodes of the first unit cell region, the emitter layer being provided to be closer to the first principal surface than the body layer is,
wherein the insulating film is also provided between the emitter layer and the trench electrode.
18. The RC-IGBT according to claim 12 , further comprising a floating layer of a second conductive type that is provided to be closer to the first principal surface than the drift layer is and is extended in the one direction, wherein
the body layer is also provided to be closer to the first principal surface than the floating layer is,
the trench electrode is provided between the hole barrier layer and the body layer, and the floating layer, and
the insulating film is provided between the trench electrode and the floating layer.
19. The RC-IGBT according to claim 18 , wherein the lower end of the floating layer is closer to the second principal surface than the lower end of the trench electrode is.
20. A method of manufacturing a semiconductor device comprising:
a first unit cell region that is extended along one direction in a plane parallel to a first principal surface in a semiconductor substrate including the first principal surface and a second principal surface;
a second unit cell region that is provided in the semiconductor substrate and is extended in the one direction, the method comprising the process of:
forming a hole barrier layer of a first conductive type extending in the one direction on the side of the first principal surface of the semiconductor substrate;
forming trenches on respective sides of the hole barrier layer in such a way as to sandwich the hole barrier layer from the both sides;
forming an insulating film on an inner surface of the trench;
filling the trench in which the insulating film is formed to form a trench electrode;
forming a body layer of a second conductive type extended in the one direction to be closer to the first principal surface than the hole barrier layer is;
forming an emitter electrode connected to the body layer;
forming a field stop layer of a first conductive type on the side of the second principal surface of the semiconductor substrate;
forming a collector layer of a second conductive type to be closer to the second principal surface than the field stop layer is in the semiconductor substrate, the method further comprising the process of:
connecting the trench electrode of the first unit cell region to a gate wiring;
connecting the trench electrode of the second unit cell region to the emitter electrode;
forming a cathode layer of a first conductive type in such a way that it extends in the one direction in the collector layer in the second unit cell region; and
connecting the field stop layer and a collector electrode by connecting the collector electrode to the cathode layer.