| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a non-volatile semiconductor storage device that can reduce a leakage current on reading operation even if the threshold voltage of a memory cell is set to a lower value in erasure operation. SOLUTION: An N-type well 2 is formed on the surface of a P-type silicon substrate 1, and a plurality of P-type wells 4 that are electrically separated one another by a trench 3 are formed on the surface of the N-type well 2. A plurality of memory cells are formed on the P wells 4. Further, a P-type contact layer 5 that is connected to a bias circuit is formed on the surface of each P-type well 4. The bias circuit can selectively apply an inverse-bias voltage between the P-type well 4 and the P-type silicon substrate 1 where no N-type source diffusion layer 7 of a selection memory cell is included on reading operation.</p> |
