| 摘要 |
<p>PURPOSE:To enhance injection efficiency at the time of writing and to output a large ON current at the time of reading by applying a reverse bias between a source and a substrate at the time of writing and a 0 bias therebetween at the time of reading. CONSTITUTION:A bias changeover switch 10 of a control gate 6 and a changeover switch 11 of a substrate bias are connected to W side at the time of writing, and bias voltages of VCG, VBG are respectively applied thereto. The switches 10, 11 are switched to R side at the time of reading, and a 0 bias is applied thereto. Thus, if the substrate bias is applied, carrier accelerating electric field is enhanced, hot carrier generation ratio is raised, electric field directed from the substrate 1 toward a floating gate electrode 5 can be further increased, and the injection efficiency can be improved. Since the bias is not applied at the time of reading, the threshold voltage of channel is decreased and an ON current at the time of reading can be increased.</p> |
