A dual-mode sensing scheme of capacitor-coupled EEPROM cell

A dual-mode sensing (DMS) scheme for a capacitor-coupled EEPROM cell is described. A memory cell structure and a sensing scheme are proposed and estimated. The memory cell combines an EEPROM cell with a DRAM cell. The DMS scheme utilizes the charge-mode sensing of the EEPROM cell. Using this DMS technique, the sensing speed can be enhanced by 36% at a cell current of 15 mu A by virtue of the additional charge-mode sensing. Furthermore, the stress applied to the tunnel oxide of the memory transistor can be relieved by decreasing the programming voltage and shortening the programming time. Therefore, with this memory cell structure and sensing scheme, it is possible to realize high-speed sensing in low-voltage operation and high endurance. >