Semiconductor device and method for manufacturing semiconductor device

Abstract

The present disclosure discloses a semiconductor device and a method for manufacturing a semiconductor device. The method for manufacturing a semiconductor device includes following steps: providing a semiconductor substrate, and forming active regions and trench isolation structures in the semiconductor substrate, wherein the trench isolation structures are located between the active regions; forming first grooves in the active regions; filling the first grooves to form inversion polysilicon layers, the inversion polysilicon layers being inversely doped with the active regions; forming second grooves, the second grooves running through the polysilicon layers and a part of the semiconductor substrate, and reserving parts of the inversion polysilicon layers located on side faces of the second grooves; and, forming buried word line structures in the second grooves.