| 摘要 |
PURPOSE:To memorize analog value by giving write-in pulse to FG type memory element's drain through high resistance, changing source potential and controlling amount of electric charge (to be injected) into FG. CONSTITUTION:By setting level of variable voltage source 17 to a prescribed value, negative write-in pulse is given from pulse source 20. At first, channel type memory element 15 is set to OFF, and high potential is impresed to drain 18 through high resistance 19 and electron is injected into suspending gate 22. When threshold voltage Vt of the memory 15 changes accordingly to amount of injection and reaches the potential of voltage source 17 corresponding to the potential between source 16 and gate 21, the memory 15 becomes ON. For this reason, injection of electron to the gate 22 stops, and thenceforth, electric charge is not to be injected even when write-in pulse is given. By changing potential of variable voltage source 17 in this manner, it is possible to accurately control amount of electric aharge being injected into suspending gate and therefore to provide a memory device capable of effectively memorizing amount of analog. |
