A FLOTOX-BASED, BIT-ALTERABLE, COMBO FLASH AND EEPROM MEMORY

摘要

A non-volatile memory array having FLOTOX-based memory cells connected by a plurality of word lines and a plurality of bit lines is disclosed. In the memory array, the FLOTOX-based memory cells in a common word line do not share a common source line. Instead, the FLOTOX-based memory cells associated with a bit line are provided with a source line laid out in parallel with the bit line to avoid punch-through leakage. The FLOTOX-based memory cells may be 2T FLOTOX-based EEPROM cells or 1T FLOTOX-based flash cells. The byte-alterable and page-alterable functions of a 2T EEPROM array and the block-alterable function of a 1T flash array are preserved. In addition, a novel bit-alterable function is added to both 2T FLOTOX-based EEPROM array and 1T FLOTOX-based flash array to reduce the unnecessary high voltage over- stress in a write operation to improve program/erasure endurance cycles.