Metal oxide semiconductor field effect transistor of buried gate channel and manufacturing method thereof

The invention discloses a metal oxide semiconductor field effect transistor of a buried gate channel and a manufacturing method thereof. The metal oxide semiconductor field effect transistor of the buried gate channel comprises a dielectric layer, a gate electrode and a buried gate channel region. The dielectric layer is located on a substrate, and the dielectric layer is provided with a groove. The gate electrode is arranged in the groove, and the gateelectrode comprises a first metal work function layer, wherein the first metal work function layer is provided with a section structure shown in the specification, and the minimum distance between each side wall of the first metal work function layer and the closest side wall of the groove is larger than zero. The buried gate channel region is located in the substrate right below the gate electrode. 本发明公开一种埋入式栅极通道的金属氧化物半导体场效晶体管及其制法，其中该埋入式栅极通道的金属氧化物半导体场效晶体管，包含一介电层、一栅极以及一埋入式栅极通道区。介电层位于一基底上，其中介电层具有一凹槽。栅极设置于凹槽中，其中栅极包含一第一金属功函数层，其中第一金属功函数层具有一「一」字型剖面结构，且第一金属功函数层的各侧壁与凹