| 摘要 |
<p>PURPOSE:To erase information by impressing a voltage higher than an informa tion writing voltage to a control gate and tunnel discharging the carrier of a floating gate to the control gate through an insulating film thereon. CONSTITUTION:In a semiconductor storage device using a MOS type transistor as a memory cell, at the time of erasing the information, a when an electron stored in the floating gate 2 is tunnel discharged, a source 3 is set to an earth potential and a high voltage generated in a boosting circuit is applied to the control gate 1. This voltage is a higher voltage than the voltage applied to the gate 1 at the time of a writing. Then, the electron stored in the gate 2 is tunnel discharged through the insulating film 21 between the gate 1 and the gate 2. In such a way, all the gates 1 are selected and the higher voltage than that at the time of the writing, thereby, memory transistors can be collectively erased.</p> |
