Semiconductor device and forming method thereof

The invention provides a semiconductor device and a forming method thereof. The semiconductor device comprises a first substrate; the first device is positioned on the first substrate; the first dielectric layer and the first conductive plug are located on the first device; the first dielectric layer is located on the first conductive plug, the first metal layer is located on the first dielectric layer and the first conductive plug, the first dielectric layer is located on the surface of the first metal layer, the first ferroelectric insulating layer is located on the surface of the first dielectric layer, and the second metal layer is located on the surface of the first ferroelectric insulating layer; a negative capacitor is formed between two layers of conductors (the first metal layer and the second metal layer) through the ferroelectric insulating layer, a positive capacitor can be formed between the two layers of conductors (the first metal layer and the second metal layer) due to the existence of the fi