Semiconductor device

A semiconductor device, comprising:

• a first electrode;
• a second electrode facing the first electrode;
• a semiconductor part provided between the first electrode and the second electrode;
• a first control electrode disposed between the first electrode and the semiconductor part inside a first trench provided in the semiconductor part, the first control electrode being electrically insulated from the semiconductor part by a first insulating film and electrically insulated from the first electrode by a second insulating film;
• and
• a plurality of second control electrodes provided between the second electrode and the semiconductor part, the second control electrode being disposed respectively inside a plurality of second trenches provided in the semiconductor part, the second control electrodes each being electrically insulated from the semiconductor part by a third insulating film and electrically insulated from the second electrode by a fourth insulating film,
• the semiconductor part including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a third semiconductor layer of the first conductivity type, a fourth semiconductor layer of the second conductivity type, a fifth semiconductor layer of the first conductivity type, and a ninth semiconductor layer of the second conductivity type,
• the first semiconductor layer extending between the first electrode and the second electrode, the first and the second trenches extending in the first semiconductor,
• the second semiconductor layer being provided between the first semiconductor layer and the first electrode, the second semiconductor layer facing the first control electrode via the first insulating film and being electrically connected to the first electrode,
• the third semiconductor layer being selectively provided between the second semiconductor layer and the first electrode, the third semiconductor layer contacting the first insulating film and being electrically connected to the first electrode,
• the fourth semiconductor layer being provided between the first semiconductor layer and the second electrode, the fourth semiconductor layer facing one of the second control electrodes via the third insulating film and being electrically connected to the second electrode,
• the fifth semiconductor layer being selectively provided between the fourth semiconductor layer and the second electrode, the fifth semiconductor layer contacting the third insulating film and being electrically connected to the second electrode,
• the ninth semiconductor layer being provided between the first semiconductor layer and the second electrode, the ninth semiconductor layer facing another second control electrode of the second control electrodes via another third insulating film and including a second-conductivity-type impurity with a lower concentration than a concentration of a second-conductivity-type impurity in the fourth semiconductor layer.