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Trench-gate MOS transistor composed of multiple conductors

  • US 7,525,133 B2
  • Filed: 12/27/2006
  • Issued: 04/28/2009
  • Est. Priority Date: 12/28/2005
  • Status: Expired due to Fees
First Claim
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1. A semiconductor device, comprising:

  • a first semiconductor layer of a first conduction type;

    a second semiconductor layer of the first conduction type formed on a surface of said first semiconductor layer;

    a semiconductor base layer of a second conduction type formed on said second semiconductor layer;

    a semiconductor diffusion layer of the first conduction type formed on a surface of said semiconductor base layer;

    a trench formed from a surface of said semiconductor diffusion layer to a depth reaching said second semiconductor layer;

    a gate electrode formed of a conductor film buried in said trench with a gate insulator interposed therebetween;

    a first main electrode brought into contact with said semiconductor diffusion layer and said semiconductor base layer; and

    a second main electrode formed on a rear surface of said first semiconductor layer,wherein said conductor film includes a first conductor film formed along an inner wall of said trench covering the trench at its bottom and side to have a recess inside said trench, the recess formed to reach the second semiconductor layer, and a second conductor film formed to fill said recess,said first and second conductor films being composed of the same material but being different in crystal grain.

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