Semiconductor device

A semiconductor device, comprising:

• a semiconductor substrate having a first-conductivity-type drift layer between a first main surface and a second main surface opposite to the first main surface;
• and
• an IGBT region and a diode region provided to be adjacent to each other in the semiconductor substrate, wherein:
• the IGBT region includes:
• a second-conductivity-type base layer provided on a front layer of the semiconductor substrate on the first main surface side;
• a first-conductivity-type emitter layer selectively provided on a front layer of the base layer on the first main surface side;
• an active trench gate including an active trench gate electrode, which is provided so as to face the drift layer via an insulating film and to which a gate voltage is applied, in each of a plurality of active trenches that are formed to be aligned in a first direction along the first main surface of the semiconductor substrate and pass through the emitter layer and the base layer;
• and
• a second-conductivity-type collector layer provided on a front layer of the semiconductor substrate on the second main surface side;
• the diode region includes:
• a second-conductivity-type anode layer provided on the front layer of the semiconductor substrate on the first main surface side;
• a first-conductivity-type cathode layer provided on the front layer of the semiconductor substrate on the second main surface side;
• and
• a dummy trench gate having a dummy trench gate electrode, which faces the drift layer via an insulating film and to which the gate voltage is not applied, in each of a plurality of dummy trenches that are formed to be aligned in the first direction of the semiconductor substrate and pass through the anode layer;
• and
• the semiconductor device further comprises:
• a boundary trench having, in a position in which the IGBT region and the diode region are adjacent to each other in plan view, a bottom surface positioned in the drift layer to be deeper than the active trench or the dummy trench, and one side wall and another side wall that face each other and connect the bottom surface and the first main surface to each other;
• and
• a boundary trench gate electrode, which faces the base layer, the anode layer, and the drift layer via a boundary trench insulating film and is provided from the one side wall side to the other side wall side of the boundary trench across a region that faces the drift layer, in the boundary trench in which the bottom surface, the one side wall, and the other side wall are covered with the boundary trench insulating film.