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

Image Number 3 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
Specializing disambiguation of a natural language expression
Jacket liner
Encoding method, decoding method, encoding device, decoding device, program, and recording medium
Method for preparing a .beta.-SiAlON phosphor
Prevention and reduction of blood loss
Phosphor, light emitting apparatus, and liquid crystal display apparatus using the same
Defect detection system and method
  Randomly Featured Patents
Gas injection dewatering process and apparatus
Image information encoding/decoding system
Method for introducing harmonics into an audio stream for improving three dimensional audio positioning
In situ control with lubricant and tracking
Phase change memory cell having vertical channel access transistor
Wiring test assembly
Ignition enhancing propellant coatings
Photocleavable and acid cleavable linkers for combinatorial chemistry
Electrode systems and methods of using electrodes
Method for producing semiconductor laser components