| 摘要 |
PURPOSE:To prevent the current concentration of a static induction type thyristor by forming a reverse conductive type high impurity layer on the emitter of the thyristor and constructing to increase the carrier injection efficency from the emitter to the base as it is separated farther from a channel unit. CONSTITUTION:A P<+> type emitter layer 6-1 having the widest width is formed at the periphery farthest from a channel unit, and an emitter shortcircuit unit N<+> type laer 12-1 is formed at the near side to the channel unit adjacent to the layer 6-1. Then, the second P<+> type layer 6-2 having narrower width than the layer 6-1 is formed adjacent to the layer 12-1. similarly, N<+> type layer 12-2, P<+> type layer 6-3,... are formed until reaching the center of the channel. Since the carrier injection efficiency will increase as it is separated farther from the center of the channel in this manner, it can prevent the current local concentration at the turn-OFF time. |
