On-chip erase pulse counter for efficient erase verify BIST (built-in-self-test) mode

Abstract

In a method and system for monitoring erase pulses applied on a sector of flash memory cells fabricated on a semiconductor substrate, a pulse counter and a pulse counter controller are fabricated on the semiconductor substrate. The pulse counter controller inputs a maximum number and outputs an indication of a sector fail if the flash memory cells of the sector do not pass erase verification with less than the maximum number of erase pulses applied on the sector during an erase verify BIST (Built-in-Self-Test) mode. In one example, the maximum number is a percentage of a diagonal total number of erase pulses needed to be applied on the sector until each flash memory cell at a diagonal location of the sector passes erase verification.

Dependencies are inferred from the claim text.