Unexpected charge losses from the floating gates of eeprom memory cells

Abstract

A new leakage effect, which undermines data retention on the floating gates of EEPROM memory cells, is presented. The effect was uncovered by chance, because an erase operation after high temperature bake led to the surprising result of a threshold voltage decrease, instead of the expected increase. A possible physical explanation for the responsible charge loss mechanism is given and is supported by a number of additional measurements.