| 摘要 |
<p>PURPOSE:To obtain a nonvolatile semiconductor memory capable of erasing a data electrically without damaging a high integration density of a memory cell by a method wherein the data is erased in such a way that an erasure voltage is impressed on only an erasure gate electrode of the memory cell while the conduction of a transistor for switching use connected between a series circuit and an erasure line is controlled selectively and, when the data is to be written and read out, a prescribed voltage is impressed on a bit line and each row line so that the data can be written or the data can be read out from the memory cell one after another. CONSTITUTION:When this invention is embodied in an E<2>PROM, this memory constitutes each series circuit 10 by using eight each of memory cells which are connected in series. One end of each circuit 10 is connected to bit lines 12 composed of metal wiring parts 23; the other end is connected to grounding lines 13 composed of an N<+> type region 21A. Furthermore, a control gate electrode of each memory cell 11 is connected to row lines 14 composed of electrodes 25; a common erasure gate electrode of each memory cell 11 is connected to erasure lines 15 via transistors 16 whose conduction is controlled by a signal of erasure-selection lines 17. By this setup, it is possible to obtain a nonvolatile semiconductor memory which can erase data selectively for each byte without damaging a high integration density of the cell.</p> |
