INSULATED GATE BIPOLAR TRANSISTOR INSPECTION METHOD AND MANUFACTURING METHOD, AND TEST CIRCUIT

PROBLEM TO BE SOLVED: To enable the saturation voltage characteristic and turn-off loss characteristic of an insulated gate bipolar transistor to be inspected without having to send a large current to it.SOLUTION: For an IGBT 2 having a p-type P- base region 11, an n-type N+ emitter region 12 formed in the P-base region 11 and an insulated gate 15 adjacent to the N+ emitter region 12 respectively provided on a principal plane of an N- layer 10 and a p-type P+ collector layer provided on the other principal plane side of the N- layer 10, measurement is made of an electron current Ie when a gate voltage Vg is applied to the insulated gate 15 and a hole current Ih due to holes injected from the P+ collector 16 into the N- layer 10. Then, based on correlation between a ratio of the hole current Ih to a collector current Ic consisting of the electron current Ie plus the hole current Ih and saturation voltage characteristics and/or turn-off characteristics, inspection is made to see if the saturation voltage characteristics and/or the turn-off characteristics are good.