| 摘要 |
PURPOSE:To enable a gate turn-off thyristor to perform turn-off operation uniformly in a plane by providing emitter layers directly under an emitter layer segments such that the region of the emitter layer outside a gate connecting terminal has a short circuit ratio higher than that of the region inside the gate connecting terminal. CONSTITUTION:Island-shaped emitter layers 1 located directly under n-type emitter layer segments 4 are short-circuited with an n-type base layer 2 by an anode electrode 6 through an n<+> layer 7 surrounding the emitter layers 1. When the layers 1 are spaced by a distance (a) under the segment 4 indicated by the dotted line and surrounded by the layer 7 as shown in the plan view, short circuit ratio is defined by a/b where (b) represents a width of the layer 1. The larger the short circuit ratio a/b is, the shorter is turn-off time and the higher is an ON voltage. Accordingly, the short circuit ratio of the anode to the segments in the outer periphery of the substrate (the region outside a gate connection terminal 11) is designed to be high. In this manner, the gate turn-off thyristor is allowed to perform a uniform turn-off operation in a plane and to have improved current blocking properties. |
