| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the need for an additional current limiting circuit by successively controlling programming parameters by writing into cells in an equilibrium between an injection current and a displacement current and forming a best programming of the cells. SOLUTION: To optimize writing into cells, it is made in an equilibirium in which cells have a constant floating gate voltage and current. Especially, to both writing of programming and that of a software after erasure, substrate area of the cells is biased to a negative voltage against a source area, and further, a control gate area of the cells applied with a ramp voltage. The gradient of this ramp voltage is selected so that an equilibirium can be achieved between an injection current made to flow into the floating gate area and a displacement current related to an equivalent capacity existing between the floating gate and the control gate area.</p> |
