Field effect transistor and method of its manufacture

  • US 6,429,481 B1
  • Filed: 11/14/1997
  • Issued: 08/06/2002
  • Est. Priority Date: 11/14/1997
  • Status: Expired due to Term
First Claim
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1. A trenched field effect transistor comprising:

  • a semiconductor substrate having dopants of a first conductivity type;

    a trench extending a predetermined depth into said semiconductor substrate;

    a pair of doped source junctions having dopants of the first conductivity type, and positioned on opposite sides of the trench;

    a doped well having dopants of a second conductivity type opposite to said first conductivity type, and formed into the substrate to a depth that is less than said predetermined depth of the trench; and

    a doped heavy body having dopants of the second conductivity type, and positioned adjacent each source junction on the opposite side of the source junction from the trench, said heavy body extending into said doped well to a depth that is less than said depth of said doped well, wherein the heavy body forms an abrupt junction with the well and the depth of the junction, relative to the depth of the well, is adjusted so that a transistor breakdown initiation point is spaced away from the trench in the semiconductor, when voltage is applied to the transistor.

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