A 16-Mb flash EEPROM with a new self-data-refresh scheme for a sector erase operation

Abstract

A 16-Mb flash EEPROM has been developed based on the 0.6-/spl mu/m 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 overcome 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 /spl mu/m/spl times/1.7 /spl mu/m, resulting in a die size of 7.7 mm/spl times/17.32 mm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>