SEMICONDUCTOR DEVICE

摘要

In a semiconductor device, a trench gate has a bottom portion in a drift layer and a communication portion extending from a surface of a base layer to communicate with the bottom portion. A distance between adjacent bottom portions is smaller than a distance between adjacent communication portions in a x-direction. A region between adjacent trench gates is divided in a y-direction into an effective region as an electron injection source and an ineffective region which does not serve as the electron injection source. An interval L1 (>0) of the ineffective region in the y-direction, a length D1 of the communication portion in the z-direction, and a length D2 of the bottom portion in the z-direction satisfy L1≦2(D1+D2). The z-direction is orthogonal to a x-y plane defined by the x-direction and the y-direction which are orthogonal to each other.

主权项

1. A semiconductor device comprising:
a first-conductivity-type collector layer along a x-y plane defined by a x-direction and a y-direction which are orthogonal to each other; a second-conductivity-type drift layer formed on a front side of the collector layer; a first-conductivity-type base layer formed on the drift layer; trench gates including trenches extending in the y-direction to form a pattern of stripes, the trenches extending from a surface of the base layer along the x-y plane to an inside of the drift layer by penetrating the base layer in a z-direction orthogonal to the x-y plane, the trench gates further including a gate insulation layer formed on walls of the trenches and a gate electrode formed on the gate insulation layer; a second-conductivity-type emitter layer formed in a surface portion of the base layer and located on a side of the trench gate; a collector electrode formed on a back side of the collector layer and electrically connected to the collector layer; and an emitter electrode electrically connected to the emitter layer and the base layer, wherein the trench gate includes a bottom portion located in the drift layer and a communication portion extending from the surface of the base layer to communicate with the bottom portion, a distance between adjacent bottom portions in the x-direction is smaller than a distance between adjacent communication portions in the x-direction, the gate insulation is thicker in the bottom portion than in the communication portion, a region between adjacent trench gates is divided into an effective region and an ineffective region in the y-direction, the effective region corresponds to the emitter layer and serves as an injection source for injecting charges into the drift layer when a voltage is applied to the gate electrode, the ineffective region does not serve as the injection source even when the voltage is applied to the gate electrode, and an interval L1 (>0) of the ineffective region in the y-direction, a length D1 of the communication portion in the z-direction, and a length D2 of the bottom portion in the z-direction satisfy the following relationship: L1≦2(D1+D2).