Semiconductor device having a gate electrode embedded in a trench
View Patent ↗To obtain a semiconductor device in which a reduction in channel formation density in a trench extending direction is suppressed, provided is a semiconductor device including a first region and a second region alternately arranged in the trench extending direction. The first region includes a first front surface semiconductor electrode layer of a first conductivity type having a portion along an outer side surface of the trench from the front surface of the semiconductor device to the first height to which a gate electrode is embedded into the trench. The second region includes a base contact region having a depth from the front surface of the semiconductor device to the second height higher than the first height and a second front surface semiconductor electrode layer of the first conductivity type from the first height to the second height.
1. A semiconductor device, comprising:
a semiconductor substrate;
a first electrode in contact with a front surface of the semiconductor substrate; and
a second electrode in contact with a back surface of the semiconductor substrate,
the semiconductor substrate comprising:
a back surface semiconductor electrode layer of a first conductivity type having a predetermined thickness from the back surface of the semiconductor substrate;
a base region of a second conductivity type above the back surface semiconductor electrode layer;
a trench having a depth from the front surface of the semiconductor substrate to an upper surface of the back surface semiconductor electrode layer;
a gate insulating film covering a bottom surface and a side surface of the trench, and having an upper end portion at a first height between the front surface of the semiconductor substrate and the bottom surface of the trench;
a gate electrode embedded in the trench and having an upper end at the first height via the gate insulating film;
an insulating film embedded in the trench on the gate insulating film and the gate electrode and extending to the front surface of the semiconductor substrate; and
a first region and a second region in contact with the trench, and alternately arranged in an extending direction of the trench,
the first region comprising:
a first front surface semiconductor electrode layer of the first conductivity type having a portion along an outer side surface of the trench from the front surface of the semiconductor substrate to the first height, and a portion in contact with the first electrode,
the second region comprising:
a base contact region of the second conductivity type having a depth from the front surface of the semiconductor substrate to a second height higher than the first height, an impurity concentration higher than an impurity concentration of the base region, a portion at least partially in contact with the base region, and a portion in contact with the first electrode; and
a second front surface semiconductor electrode layer having a portion along the outer side surface of the trench from the first height to the second height, and a portion in contact with the first front surface semiconductor electrode layer on a surface perpendicular to the extending direction of the trench.
2. The semiconductor device according to claim 1 , wherein the second front surface semiconductor electrode layer has an upper surface in contact with a lower surface of the base contact region.
3. The semiconductor device according to claim 1 , wherein the second front surface semiconductor electrode layer has an upper portion in contact with the first electrode.
4. The semiconductor device according to claim 1 , wherein the semiconductor device comprises an insulating gate bipolar transistor comprising a collector layer of the second conductivity type between the back surface semiconductor electrode layer and the second electrode.
5. The semiconductor device according to claim 2 , wherein the semiconductor device comprises an insulating gate bipolar transistor comprising a collector layer of the second conductivity type between the back surface semiconductor electrode layer and the second electrode.
6. The semiconductor device according to claim 3 , wherein the semiconductor device comprises an insulating gate bipolar transistor comprising a collector layer of the second conductivity type between the back surface semiconductor electrode layer and the second electrode.