The present invention provides a semiconductor device, which includes a substrate and a sensing memory device. The substrate includes a metal-oxide-semiconductor transistor having a gate. The sensing memory device is disposed on the gate of the metal-oxide-semiconductor transistor and includes followings. The second conductive layer is covering the first conductive layer. The charge trapping layer is disposed between the first conductive layer and the second conductive layer, wherein the first conductive layer has a sensing region therein when charges stored in the charge trapping layer, and the sensing region is adjacent to the charge trapping layer. The first dielectric layer and the second dielectric layer are respectively disposed between the charge trapping layer and the first conductive layer and between the charge trapping layer and the second conductive layer, wherein a third dielectric layer is disposed between the gate and the sensing memory device.