SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To accurately convert incident light into electrical signals in a photo sensor.SOLUTION: An embodiment of a semiconductor device has a photo diode, a first transistor and a second transistor. The photo diode has a function of supplying charge depending on incident light to a gate of the first transistor. The first transistor has a function of storing charge supplied to the gate. The second transistor has a function of retaining charge stored in the gate of the first transistor and the second transistor is formed by using an oxide semiconductor.