The present application relates to a semiconductor device, comprising a substrate, with a body region being formed on the substrate, and a well region being formed in the body region; and further comprising trenches penetrating through the well region and the body region and extending to the substrate, wherein a first polysilicon body and a second polysilicon body, which are isolated from each other, are respectively formed at the bottom and the top of each trench to form a split gate structure, the trenches are filled with an inter-layer dielectric layer, a conductive plug penetrating through the inter-layer dielectric layer and extending into the first polysilicon body is formed in each trench, the conductive plug is isolated from the second polysilicon body by means of the inter-layer dielectric layer, the conductive plug is connected to a source electrode, and the second polysilicon body is connected to a gate electrode.