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Semiconductor memory using trench capacitor

  • US 4,860,071 A
  • Filed: 02/10/1988
  • Issued: 08/22/1989
  • Est. Priority Date: 03/08/1985
  • Status: Expired due to Term
First Claim
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1. A semiconductor memory comprising:

  • a plurality of word lines, data lines and memory cells that are disposed on a semiconductor substrate of a first conductivity type, wherein said memory cells are arranged in matrix;

    data storage portions formed for each of said memory cells, wherein each of said data storage portions comprises;

    first and second trenches formed in said substrate,an impurity doped region having a second conductivity type opposite to said first conductivity type, wherein said impurity doped region is formed in said substrate so as to extend between a side wall of the first trench and a side wall of said second trench,at least one insulating film formed on said side walls of said first and second trenches, anda plate electrode disposed on said insulating film in both said first and second trenches,wherein a first capacitance for said data storage portions is formed by the impurity doped region, a first portion of the plate electrode which is disposed in the first trench and a second portion of the insulating film which is disposed between the impurity doped region and the first portion of the plate electrode, wherein a second capacitor for said data storage portion is formed by the impurity doped region, a second portion of the plate electrode which is disposed in the second trench and a second portion of the insulating film which is disposed between the impurity doped region and the second portion of the plate electrode, and further wherein the second trench isolates data stored in the first capacitor from data storage portions of other memory cells, andswitches formed for each of said memory cells to connect each memory cell to a data line, wherein each switch includes an MOS transistor having one of a source electrode or a drain electrode connected to the impurity region of said data storage portion and having a gate electrode connected to said word line.

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