A semiconductor device and methods for forming the same are provided. The method includes providing a substrate having a first conductive type, forming an epitaxial layer having the first conductive type on the substrate, forming a trench in the epitaxial layer, forming a first insulating layer in the trench and on the top surface of the epitaxial layer, forming a shield electrode and a mask layer on the first insulating layer in order, using the mask layer to remove a portion of the first insulating layer, wherein the top surface of the first insulating layer is higher than the top surface of the shield electrode after removing the portion of the first insulating layer, removing the mask layer, forming a second insulating layer on the first insulating layer and the shield electrode, and forming a gate electrode on the second insulating layer.