| 摘要 |
<p>PURPOSE:To combine a volatile semiconductor storage device with a nonvolatile semiconductor storage device so as to enable rewriting or maintenance of memory at need by coupling and uniting the control gate of a MOS transistor which constitutes a nonvolatile semiconductor storage device and has a floating gate with the control gate of a MOS transistor which constitutes a semiconductor device for mode change-over. CONSTITUTION:A capacity element C is connected to the middle point 4 between a MOS transistor MT, and a MOS transistor MT2, and specified voltage is applied from a terminal 5. The terminal 1 of the MOS transistor MT, usually becomes the n-layer of a semiconductor, and it is connected to the column of a memory, and the terminal 3 of a gate G, is connected to the line of the memory. The MOS transistor MT2 constitutes EEPROM, being provided with a floating gate 6 below a usual control gate G2. A MOS transistor MT3 is a transistor for changing over mode of whether this memory operates as EEPROM or operates DRAM, and it is so arranged that the voltage may be applied from a terminal 7 to that gate G3 and the gate G2 of the MOS transistor MT3.</p> |
