| 摘要 |
<p>PURPOSE: To erase an erasable PROM (EPROM) without deteriorating its cells by connecting the drain, source and channel of the memory cell and impressing a positive square voltage signal between the cell and a control gate. CONSTITUTION: The drain 3, source 4 and channel 8 of the memory cell to be erased are connected and the positive square voltage of about 13V meeting the thickness of a gate oxide layer 7 is impressed between the cell and the control gate 6. As a result, the free carriers accumulated in a floating gate 2 partly arrive at a substrate 5 across the gate oxide layer 7 only at the time of the rising edge of the square wave signal by a hot carrier effect. The extraction of the whole of the free carrier implanted into a program is, therefore, made possible by impressing the continuous square signals. Then, the erasing current is small and the erasure is executable without the deterioration of the cell.</p> |
