| 摘要 |
PURPOSE:To contrive the improvement of a turn-off dielectric strength while keeping a low on-voltage, by using a wafer having a bonding boundary in a predetermined position in a D-base layer and utllizing a direct bonding technique. CONSTITUTION:By using a wafer made of two semiconductor substrates bonded directly, a direct bonding boundary 16 exists in first conductivity type base layers 13 and 15 and a distance between this boundary and a second conductivity emitter layer 17 is made 30mum or shorter. In such structure, a maximum impurity concentration part of the first conductivity type base layers 13 and 13 can be arranged in the position distant from a bonding plane between the second conductivity emitter layer 17 and the first conductivity base layer 15. As a result, although a lateral-direction resistance of the first conductivity base layers 13 and 15 which is to be a passage of a gate current is virtually reduced, an impurity concentration of a bonding part between the first conductivity type base layer 15 and the second conductivity type emitter layer 17 is low and a breakdown voltage in the bonding part is high. Also, an emitter injection efficiency can be made high and an on-voltage is low and a turn-off breakdown strength is high. |
