A control-gate-assisted erasing method for a single-poly EEPROM cell with metallic control gate structure

摘要

A control-gate- (CG) assisted erasing method is investigated for the embedded single-poly EEPROM cell with metallic CG structure. Without the CG bias polarity limitation, which suffers in the diffused n-well CG EEPROM cells, the metallic CG cells can apply negative voltage at CG. By negatively biasing the CG, an enhanced electric field, and thus an improved erasing speed can be achieved for the source erasing. With the channel hot electron (CHE) programming and the enhanced erasing method, an enlarged threshold window can be obtained. In addition, the reliability of the EEPROM cell fabricated with the foundry standard CMOS process with an enhanced erasing method is studied.