×

Field effect Trench transistor having lightly doped epitaxial region on the surface portion thereof

  • US 5,910,669 A
  • Filed: 07/24/1992
  • Issued: 06/08/1999
  • Est. Priority Date: 07/24/1992
  • Status: Expired due to Term
First Claim
Patent Images

1. A field effect transistor comprising:

  • a substrate of a first conductivity type being a drain region;

    a lower layer of the first conductivity type fortmed on the substrate and having a doping level less than that of the substrate;

    an upper layer of the first conductivity type formed on the lower layer and having a doping level less than that of the lower layer;

    a trench defined in only the upper layer and extending to within a predetermined distance of the lower layer, the trench being at least partially filled with a conductive gate electrode;

    a source region of the first conductivity type formed in the upper layer and extending to a principal surface of the upper layer and lying adjacent to the sidewalls of the trench; and

    a body region of a second conductivity type extending from the principal surface of the upper layer down to and into at least an upper portion of the lower layer and being spaced apart from the lower portion of the trench, wherein two spaced apart portions of the body region lying respectively on two sides of the trench define a lateral extent of the upper layer.

View all claims
  • 5 Assignments
Timeline View
Assignment View
    ×
    ×