A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a substrate and at least a gate trench extending along a first direction formed in the substrate. A gate dielectric layer is formed conformally covering the gate trench. A gate metal is formed on the gate dielectric layer and filling the gate trench. A plurality of intervening structures are arranged along the first direction in a lower portion of the gate trench and disposed between the gate metal and the gate dielectric layer.