| 摘要 |
A memory device without additional logic circuits, including a memory cell which cannot be accessed by a third party and which is always accessible when needed. One embodiment is a memory device including a first memory cell and a second memory cell, and the second memory cell includes a second transistor having a second channel formed of an oxide semiconductor film. Data is read from the second memory cell when the second transistor is being irradiated with ultraviolet rays. |
