Soft Programming in Scaled Flash EEPROM Cells

This paper reports new results on programming performances and soft programming characteristics of scaled Flash memory cells fabricated with conventional and innovative p-pocket technologies. Soft-programming lifetimes of several devices are derived according to different procedures based on the effective temperature model of low voltage hot carriers (ETM). The results show that: a) these procedures, although not fulfilling all the assumptions of the ETM, provide lifetime estimations in good reciprocal agreement; b) constant read voltages VDR = 1 ±0.1V can be maintained in scaled p-pocket cells only if the cell architecture is tuned to comply with soft-programming requirements. The improved current drive capability of these cells can be traded in order to get more reliable operation at constant read current.