Silicon carbide device with trench gate structure and forming method thereof

The invention provides a silicon carbide device with a trench gate structure and a forming method thereof, the silicon carbide device comprises a substrate, the substrate comprises a silicon carbide substrate and a silicon carbide epitaxial layer located on the surface of the silicon carbide substrate, the silicon carbide epitaxial layer comprises an x direction and a y direction which are perpendicular to each other, a buried doped region and a gate trench which extend in the x direction and the y direction respectively are formed in the silicon carbide epitaxial layer, and the bottom surface of the gate trench is flush with the top surface of the buried doped region; the second highly doped region is located in a part of the silicon carbide epitaxial layer close to the side wall of the top of the gate trench; the gate dielectric layer is located at the bottom and the side wall of the gate trench, and the top surface of the gate dielectric layer is flush with the top surface of the second highly doped region