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Semiconductor device and method of manufacturing the same

  • US 6,144,079 A
  • Filed: 10/03/1996
  • Issued: 11/07/2000
  • Est. Priority Date: 04/01/1996
  • Status: Expired due to Fees
First Claim
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1. A semiconductor device, wherein first and second MIS transistors of the same conductivity type are formed at a main surface of a semiconductor substrate, and concentration profiles of one identical conductivity type impurity in sections extending through channel regions of said first and second MIS transistors in a depth direction from said main surface of said semiconductor substrate have peaks at different depths, whereinsaid first MIS transistor has a first channel region provided with a first impurity layer under said first channel region, and said second MIS transistor has a second channel region provided with a second impurity layer having the same conductivity type as said first impurity layer under said second channel region;

  • andsaid second MIS transistor has a higher threshold voltage than said first MIS transistor, and said first impurity layer is formed at a position deeper from said main surface than said second impurity layer.

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