Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate which has an upper surface and which is provided with a drift region of a first conductivity type;
• a plurality of trench portions which are provided from the upper surface toward an inside of the semiconductor substrate and which extend in an extending direction;
• a plurality of mesa portions each being a region sandwiched between two of the trench portions;
• an emitter electrode provided above the upper surface of the semiconductor substrate;
• and
• an interlayer dielectric film which is provided between the upper surface of the semiconductor substrate and the emitter electrode and in which a contact hole is formed, wherein
• the plurality of mesa portions include:
• one or more channel mesa portions each having an emitter region of the first conductivity type provided on the upper surface of the semiconductor substrate and a base region of a second conductivity type provided between the emitter region and the drift region, and each being connected to the emitter electrode by the contact hole;
• and
• one or more floating mesa portions, in each of which the contact hole is not provided thereabove or in each of which a length of the contact hole above in the extending direction is shorter than a length of the contact hole above the one or more channel mesa portions, and wherein
• at a lower end of at least one of the trench portions sandwiching each of the one or more channel mesa portions, a second trench bottom region of the second conductivity type having a higher concentration than the base region is provided.