| 摘要 |
<p>PURPOSE:To program to the state higher than a ternary by storing a charge less than that at the time of the program of an off state on a gate film and setting a state for passing a current lower than an on current and higher than an off current. CONSTITUTION:A memory cell consisting of a floating gate type MOSFETM0 and a selecting N channel MOSFETQ0 is connected to a program circuit 1. Initially, a CPU 2 switches a switch 10 to (a) side. Then, a direct current voltage VCC is boosted to the direct current voltage VPP of 14V, for instance by a boosting circuit 15 and impressed to the gate of a FETM0 for a prescribed time. Thereby, when the FETM0 impresses a prescribed reading voltage, it is turned off. Then, the CPU 2 switches the switch 10 to a (b) side to turn on a switch 20 and turn on the FETQ0. Then, the CPU 2 turns on the FETQ0 to impress the voltage VPP to the gate and the drain of the FETM0 for the prescribed time and set the FETM0 to the third state for passing the current lower than the on current and higher than the off current.</p> |
