Field effect transistor and method of its manufacture

  • US 6,710,406 B2
  • Filed: 05/24/2002
  • Issued: 03/23/2004
  • 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 to a first 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 second depth that is less than said first depth of the trench; and

    a heavy body formed in said doped well extending to a third depth that is less than said second depth of said doped well, the heavy body forming an abrupt junction with the well;

    wherein, a location of the abrupt 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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