Abstract
Novel device technologies for a 5-V-only EEPROM (electrically erasable programmable read-only memory) with a NAND structure cell are described. By applying half of the programming voltage to unselected bit lines and a successive programming sequence, the NAND structure cell keeps a wide threshold margin. A high-voltage CMOS process realizes reliable programming characteristics. The reliability of the cell has been confirmed experimentally. Using 1.0-μm design rules, the unit cell area per bit is 12.9 μm 2 , which is small enough to realize a 4-Mb EEPROM.