| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device that can reduce a chip area without complicating control for erasing processing in erasing processing in memory cell block units and without providing a boundary area for electrically insulating one memory cell block from the other. <P>SOLUTION: The nonvolatile semiconductor memory device in which memory cells are arranged in a matrix shape in row and column directions in a second conductive type well region formed in a first conductive type semiconductor substrate, and a memory cell allay is formed by connecting control gates of memory cells in the same row to a common word line, divides the memory cell array into a plurality of memory cell blocks configured with a plurality of word lines and performs erasing processing in memory cell block units. The nonvolatile semiconductor memory device performs erasing processing by applying a positive voltage for erasure to the well region, a negative voltage with the same value as the positive voltage for erasure to all the word lines in blocks to be erased, a positive voltage for erasure to control gates of all the memory cells included in memory cell blocks except the blocks to be erased. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
