Electrically erasable and programmable read only memory device equipped with inspection circuit for threshold levels of memory cells

摘要

An electrically erasable and programmable read only memory device enters an automatic erasing mode of operation, and repeats short erasing operation followed by confirmation of proper erased state in the automatic erasing mode, wherein the memory cell array is inspected to see whether or not each memory cell not only enters the erased state but also remains in enhancement mode so that the memory cell array is exactly programmed in a programming mode of operation.