METHOD FOR SETTING THE ERASE STARTING BIAS IN FLASH MEMORY DEVICE AND METHOD FOR ERASING THE FLASH MEMORY DEVICE USING THE SAME

摘要

A method for setting the erase starting bias in flash memory device is provided to improve the reliability of the flash memory device by controlling the right side level of the threshold voltage distribution of the memory cell. A method for setting the erase starting bias in flash memory device is comprised of the steps: performing erase operation by supplying the first erase bias to the memory cell(210); verifying the erase state of the memory cell(220); supplying a predetermined scan bias pulse is applied to the memory cell(240); determining a pass state by supplying the pulse of the scan bias(250); calculating the deviation of the cell threshold voltage and cell threshold voltage from reserved elimination if the decision result is fail.(260~270); setting the voltage added to the first bias by deviation is set up as the elimination beginning bias(280); performing elimination by the set up elimination beginning bias(290).