| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage element and a nonvolatile semiconductor storage device capable of dispensing with verifying operation and actualizing more than two kinds of threshold voltages. <P>SOLUTION: The nonvolatile semiconductor storage element has: a semiconductor substrate; a semiconductor region 2c of a first conductivity type provided in the semiconductor substrate; source and drain regions 2a and 2b of a second conductivity type provided apart from each other; a first insulating layer 3 provided between the source and drain regions; a charge storage layer 4 which has a layered structure provided on the first insulating layer and including at least four layers of conductor films 4a, 4c, 4e, and 4g and inter-conductor insulating films 4b, 4d, and 4f provided between conductor films, wherein a dielectric constant of an inter-conductor insulating film disposed away from the semiconductor substrate is higher than a dielectric constant of an inter-conductor insulating film disposed nearby the semiconductor substrate and dielectric constants of any of the inter-conductor insulating films is lower than the dielectric constant of the first insulating layer 3; a second insulating layer 5 provided on the charge storage layer and having a higher dielectric constant than that of any of the inter-conductor insulating films; and a conductor layer 6. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
