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SEMICONDUCTOR DEVICE

  • US 20140217464A1
  • Filed: 09/13/2012
  • Published: 08/07/2014
  • Est. Priority Date: 09/27/2011
  • Status: Active Grant
First Claim
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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, whereinthe 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, andan 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).

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