Semiconductor device and method for forming the same

The present invention discloses a semiconductor device and a method for forming the same. The semiconductor device has a substrate, a grid dielectric layer, a source and a drain and a grid. The substrate has a groove, the grid dielectric layer is arranged in the groove and has a flat upper surface and a protruded edge, and the protruded edge protrudes the flat upper surface along a direction substantially vertical with the substrate. The drain and the source are arranged at the opposite edges of the grid dielectric layer, the grid is formed on the grid dielectric layer, and the grid and the protruded edge of the grid dielectric layer are not overlapped with each other along a direction substantially parallel with the substrate. 本发明公开种半导体元件及其制造方法。半导体元件包括基底、栅极介电层、漏极及源极以及栅极。基底具有凹槽。栅极介电层设置于凹槽中，栅极介电层具有平坦上表面及突出边缘，突出边缘沿着实质上垂直于基底的方向突出于平坦上表面。漏极及源极设置于栅极介电层的相对侧边。栅极形成于栅极介电层上，栅极与栅极介电层的突出边缘沿着实质上平行于基底的方向彼此不交叠。