Flash memory having low threshold voltage distribution

摘要

A flash memory device having a low threshold voltage distribution is disclosed. The threshold voltage in a program state of a flash memory cell is defined to be near or slightly greater than approximately 3.0 volts. The threshold voltage in an erased state is defined to be less than 0.7 volts or at ground level. The low threshold voltage distribution makes it possible to use a low voltage around 3.0 volts for the gate of the memory cell in a read operation. The UV erased threshold is raised to near the threshold voltage of a program state to avoid data retention problem.