| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device capable of reducing on-voltage and improving reliability, and to provide a method for controlling a semiconductor device, and a method for evaluating the same.SOLUTION: A front surface of a semiconductor substrate is provided with a MOS structure of a trench gate type composed of a gate trench 4, a gate insulating film 5, and a gate electrode 6 and a dummy trench gate structure composed of a dummy trench 14, a dummy gate insulating film 15, and a dummy gate electrode 16. When a wafer is inspected, a DC power supply 21 is connected between an emitter pad E and a dummy gate pad DG connecting the dummy gate electrode 16 to apply voltage. This allows for evaluation of a withstand voltage of the dummy gate insulating film 15. Alternatively, the dummy gate electrode 16 and an emitter electrode 7 are connected via a diode, and the dummy gate electrode 16 and the gate electrode 6 are connected via a resistor. This allows for constant keeping of the dummy gate electrode at positive potential when IGBT is on. |
