| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve retention performance of an electrically rewritable nonvolatile memory cell. <P>SOLUTION: The semiconductor device includes: a memory array (19) containing 1-bit twin cells, each composed of electrically rewritable first storage devices (MC1) and second storage devices (MC2) holding binary data according to difference of their threshold voltages and having different retention characteristics depending on difference of the binary data thereof; and a read circuit (SA) for differentially amplifying complementary data output from the first and second storage devices of the twin cell selected for read, and judging the information stored in the twin cell. Although the retention characteristics differ depending on difference of the binary data as the property of memory cells, two memory cells constituting a twin cell are arranged to hold different data. Therefore, even when the retention performance of one memory cell deteriorates, the difference between data held by the two memory cells is maintained. Hence, differential amplification of such difference enables acquisition of proper storage information. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
