Semiconductor device and method for manufacturing semiconductor device

A semiconductor device comprising:

• a semiconductor substrate of a first conductivity type, having a first principal surface, and a second principal surface on an opposite side from the first principal surface;
• a first trench provided in the first principal surface;
• a second trench provided in the first principal surface;
• a first semiconductor layer of a second conductivity type, provided in the first principal surface between the first trench and the second trench;
• a second semiconductor layer of the first conductivity type, provided in the first principal surface at a position sandwiching the first trench between the second semiconductor layer and the first semiconductor layer, and making contact with the first trench;
• a third semiconductor layer of the second conductivity type, provided under the second semiconductor layer, and making contact with the second semiconductor layer and the first trench;
• a fourth semiconductor layer of the first conductivity type, provided under the third semiconductor layer, and making contact with the third semiconductor layer but separated from the first trench;
• a fifth semiconductor layer of the second conductivity type, provided in the first principal surface at a position sandwiching the second trench between the fifth semiconductor layer and the first semiconductor layer;
• a first insulating film provided on an inner wall of the first trench;
• a first gate trench electrode provided inside the first trench via the first insulating film, and opposing the third semiconductor layer;
• a second insulating film provided on an inner wall of the second trench;
• a first emitter trench electrode provided inside the second trench via the second insulating film;
• a gate electrode connected to the first gate trench electrode;
• an emitter electrode connected to the first emitter trench electrode;
• and
• a collector electrode provided in the second principal surface,
• wherein a lower end of the fifth semiconductor layer is located at a position lower than or equal to a position of a lower end of the third semiconductor layer.