A 16-MB FLASH EEPROM WITH A NEW SELF-DATA-REFRESH SCHEME FOR A SECTOR ERASE OPERATION

A 16-Mb flash EEPROM has been developed based on the 0.6-mum triple-well double-poly-si single-metal CMOS technology. A compact row decoder circuit for a negative gate biased erase operation has been designed to obtain the sector erase operation. A self-data-refresh scheme has been developed to overcome the drain-disturb problem for unselected sector cells. A self-convergence method after erasure is applied in this device to over-come the overerase problem that causes read operation failure. Both the self-data-refresh operation and the self-convergence method are verified to be involved in the autoerase operation. Internal voltage generators independent of the external voltage supply and temperature has been developed. The cell size is 2.0 mum x 1.7 mum, and the die size has resulted in 7.7 mm x 17.32 mm.