180nm 4Mb High Speed High Reliability Embedded SONOS Flash Memory

A 1.8/3.3V 4Mb (512K times 8 bit) embedded SONOS flash memory has been successfully developed and verified with 180nm CMOS logic compatible integrated technology, in which a reverse programming array architecture and a novel high speed sensing circuit with dual-phase precharge path and self-adjusted load are proposed to improve read speed. Moreover, a novel threshold voltage tracking technique is also introduced to improve the reliability. Finally, a 4.4 mm² core size and a 0.40 mum² (12.4F²/bit) cell size are obtained, and the test results show that the read speed and the endurance characteristics are 17ns and 10⁵, respectively