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Semiconductor device

  • US 20050161732A1
  • Filed: 01/21/2005
  • Published: 07/28/2005
  • Est. Priority Date: 01/23/2004
  • Status: Active Grant
First Claim
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1. A semiconductor device comprising:

  • a semiconductor substrate of a first conductivity type, which has a first major surface and a second major surface;

    a lightly-doped semiconductor layer of the first conductivity type, which is formed on the first major surface of the semiconductor substrate;

    a first semiconductor region of the first conductivity type, which is formed on a top of an island-shaped region on a surface of the lightly-doped semiconductor layer;

    a first electrode, which surrounds the first semiconductor region and is buried in the lightly-doped semiconductor layer to a deeper position than the first semiconductor region;

    a second semiconductor region which is formed on the second major surface of the semiconductor substrate;

    a buried field relaxation layer which is formed in the lightly-doped semiconductor layer between a bottom surface of the first electrode and the second semiconductor region, the buried field relaxation layer including a first field relaxation layer of the first conductivity type and second field relaxation layers of the second conductivity type formed at two ends of the first field relaxation layer;

    a second electrode which is formed on the first semiconductor region on the first major surface; and

    a third electrode which is formed on the second semiconductor region on the second major surface.

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