| 摘要 |
<p>PURPOSE:To suppress the avalanche breakdown of a source region and to prevent the deterioration of erasing characteristics by a method wherein the drain region of a nonvolatile semiconductor memory element is brought into an open- circuit state, the voltage one half or less the junction breakdown voltage of a source region is applied to the source region, and negative voltage is applied to a control gate electrode. CONSTITUTION:The write-in operation when programming is conducted in such a manner that a semiconductor substrate 1 and a source region 2 are grounded, a saturation region is operated by applying 12V volts to a control gate electrode 7 and 7V volts to a drain region 3, and the channel hot electrons generated in the vicinity of the drain region 3 are injected to a floating gate electrode 5. Also, an erasing operation is conducted in such a manner that the substrate 1 is grounded, the drain region 3 is brought into an open-circuit state, and the voltage one-half or less the junction breakdown voltage is applied to the source region 2. Negative voltage is applied to the control gate electrode 7, and the electrons accumulated on a floating gate electrode 5 are discharged by the Fowler-Nordheim tunnel effect.</p> |
