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Nonvolatile semiconductor memory device

  • US 5,962,891 A
  • Filed: 10/03/1996
  • Issued: 10/05/1999
  • Est. Priority Date: 10/03/1995
  • Status: Expired due to Fees
First Claim
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1. A semiconductor device comprising:

  • a semiconductor substrate of a first conductivity type;

    at least two transistors each including,a source having an impurity of a second conductivity type in said semiconductor substrate diffused to a first depth;

    a drain of the second conductivity type, electrically separated from said source and formed on a surface of said semiconductor substrate;

    a first insulating film formed on a surface of a channel region between said source and said drain;

    a first gate electrode formed on a surface of said first insulating film; and

    a second insulating film formed on a surface of said first gate electrode; and

    a source wiring layer connected to said source of each of said at least two transistors and having the impurity of the second conductivity type in said semiconductor substrate diffused to a second depth shallower than the first depth.

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