NONVOLATILE SEMICONDUCTOR STORAGE DEVICE

摘要

PURPOSE:To shorten the erasure time by providing an erased information holding means between a block selecting means and a block erasing means. CONSTITUTION:The erased information holding means 201 is provided between the block selecting means 200 and block erasing means 203. Block erasure in a NAND type EEPROM is performed by selectively holding all selection gate lines of one NAND bundle at 0V and gate lines of an unselected NAND bundle at Vpp. A row main decoder 200 selects one of batch erasure block 203 and a subordinate decoder 202 serves as a memory cell erasing means in the block 203 during the erasure. At the time of the block erasure, the erased information of the decoder 200 is held in a latch circuit 201 in order and the block erasing means operates according to the stored erased information to erase all nonvolatile memory cells of the corresponding batch erasure block 203. Thus, plural batch erasure blocks can be erased at the same time and the erasure time is shortened.