US Patent 11177262 Semiconductor device or memory device

A novel semiconductor device is provided. Alternatively a memory device which can retain more multi-level data is provided. One of a source or a drain of a write transistor is electrically connected to a bit line, and the other of the source or the drain of the write transistor is electrically connected to a data retaining portion. Data written to the data retaining portion is provided to the data retaining portion through a write bit line and the write transistor. Rising of a threshold voltage which is caused in a write operation can be inhibited and more multi-level data can be retained(stored) through electrically connecting a back gate of the write transistor to the write bit line.