Resources Contact Us Home
Method to increase coupling ratio of source to floating gate in split-gate flash

Image Number 5 for United States Patent #7001809.

A split-gate flash memory cell having a three-dimensional source capable of three-dimensional coupling with the floating gate of the cell, as well as a method of forming the same are provided. This is accomplished by first forming an isolation trench, lining it with a conformal oxide, then filling with an isolation oxide and then etching the latter to form a three-dimensional coupling region in the upper portion of the trench. A floating gate is next formed by first filling the three-dimensional region of the trench with polysilicon and etching it. The control gate is formed over the floating gate with an intervening inter-poly oxide. The floating gate forms legs extending into the three-dimensional coupling region of the trench thereby providing a three-dimensional coupling with the source which also assumes a three-dimensional region. The leg or the side-wall of the floating gate forming the third dimension provides the extra area through which coupling between the source and the floating gate is increased. In this manner, a higher coupling ratio is achieved without an increase in the cell size while at the same time alleviating the punchthrough and junction break-down of source region by sharing gate voltage along the side-wall.

  Recently Added Patents
Representations of compressed video
Semiconductor device comprising a Fin and method for manufacturing the same
Method and devices for handling access privileges
Location-based method to specify ratio frequency spectrum rights
System and method for the heterologous expression of polyketide synthase gene clusters
Defected ground plane inductor
Etching method, etching apparatus, and computer-readable recording medium
  Randomly Featured Patents
Display unit for cabinetry
Method of laying a cable or pipe
Cantilevered, adjustable, portable computer desk
Dispenser for dispensing a product
Agents for potentiating the effects of antitumor agents and combating multiple drug resistance
Taxoids, preparation thereof and pharmaceutical Compositions containing same
Multi-piece solid golf ball
Anterior antenna casing for a magnetic resonance imaging receive coil
System and method for testing electronic device