A 1 Mb 5 V-only EEPROM (electrically erasable programmable ROM) with metal-oxide-nitride-oxide-semiconductor (MONOS) memory cells specifically designed for a semiconductor disk application is described. The memory has high endurance to write/erase cycles and a relatively low programming voltage of +or-9 V. These advantages result from the structure and the characteristics of the MONOS memory cell. A newly developed dual-gate-type MONOS memory cell has a small unit cell area of 18.4 mu m/sup 2/ with 1.2 mu m lithography, and the die size of the fabricated chip is 5.3 mm*6.3 mm. A new programming scheme called multiblock erase solved the problem of slow programming speed. A programming speed of up to 1.1 mu s/B equivalent (140 ms/chip) was obtained.<>