| 摘要 |
<p>PURPOSE:To detect charge amount in floating gate electrode in a memory cell by applying the second voltage with respect to the first semiconductor region to a drain region. CONSTITUTION:The writing and erasing voltage of a non-volatile semiconductor memory utilizing tunnel injection means largely depend upon the type and thickness tox of a thin insulating film 5. When the thickness tox of the film 5 is reduced, memory holding time can be shortened as the increase of the number of rewritings, and when the thickness is increased, the holding time can be lengthened as the increase of the number of rewritings. Accordingly, when the memory is produced by selecting suitable thickness, the thickness which does not reduce the holding time can be obtained by the increase of the number of rewritings, thereby forming a low program voltage non-volatile semiconductor memory having long holding time.</p> |
