Semiconductor device and manufacturing method

A semiconductor device, comprising:

• a semiconductor substrate which includes a drift region of a first conductivity type;
• a plurality of trench portions which are provided from an upper surface of the semiconductor substrate up to the drift region, and arranged in an arranging direction in the upper surface of the semiconductor substrate;
• and
• a mesa portion which is a region interposed by two of the trench portions in the semiconductor substrate,
• wherein the trench portions include one or more gate trench portions and one or more dummy trench portions,
• wherein at least one mesa portion in contact with the gate trench portion includes,
• an emitter region, having a first conductivity type of a doping concentration higher than the drift region, which is provided to be exposed to the upper surface of the semiconductor substrate and to be in contact with the gate trench portion,
• a base region, having a second conductivity type, which is provided on a lower side of the emitter region and in contact with on the gate trench portion,
• an accumulation region, having the first conductivity type of a doping concentration higher than the drift region, which is provided on a lower side of the base region, and
• an intermediate region, having the second conductivity type, which is provided at a depth position between an upper end of the base region and a lower end of the accumulation region,
• wherein the base region has a first peak in a doping concentration distribution in a depth direction of the semiconductor substrate, and
• wherein the intermediate region has at least one of a second peak and a kink portion from the first peak to a depth position of a lower end of the trench portion in a doping concentration distribution in the depth direction.