| 摘要 |
<p>PURPOSE:To provide a writing and an erasing method by which a nonvolatile memory cell having excellent reliability and a long life can be obtained. CONSTITUTION:A source 3 and a substrate 1 are grounded, and a positive voltage with respect to the substrate 1 is so applied to a control gate as to generate an electric field of such a strength as required to produce a tunnel effect in an insulating film 6c and at the same time a positive voltage of the same degree as that is applied to a drain 2, and at that time electrons pass through an insulating film 6c on the source 3 side by the tunnel effect through the source 3 from the substrate 1 and are injected into a floating gate 5 to complete the writing. The control gate 7, the source 3 and the substrate 1 are grounded, and a positive voice with respect to the substrate 1 is so applied to the drain 2 as to generate an electric field of such a strength as required to produce a tunnel effect, and at that time electrons stored under the floating gate 5 (thickness directly under is 10 to 300Angstrom ) pass through the insulating films 6c on the drain 2 side from the floating gate 5 by the tunnel effect through the drain 2 and then are discharged into the substrate 1 to complete the erasing.</p> |
