Semiconductor device for masking data stored in twin cell and outputting masked data

摘要

A memory array includes a plurality of twin cells, each of the twin cells composed of a first storage element and a second storage element configured to hold binary data according to a difference in threshold voltage between them, the first storage element and the second storage element each being electrically rewritable. Upon receiving a request to read the twin cell, when the threshold voltage of the first storage element forming the twin cell is lower than an erasure determination level and the threshold voltage of the second storage element forming the twin cell is lower than the erasure determination level, an output circuit masks the data stored in the twin cell and outputs the masked data.