Buried-channel MOSFET and a surface-channel MOSFET of a same type and fabrication method thereof

摘要

A method is provided for fabricating a buried-channel MOSFET and a surface-channel MOSFET of the same type and different gate electrodes on a same wafer. The method includes providing a semiconductor substrate having a well area and a plurality of shallow trench isolation structures; forming a threshold implantation region doped with impurity ions opposite of that of the well area in the well area for the buried-channel MOSFET; forming a gate structure including a gate dielectric layer and a gate electrode on the semiconductor substrate, wherein the gate electrode of the buried-channel MOSFET is doped with impurity ions with a same type as that of the well area, and the gate electrode of the surface-channel MOSFET is doped with impurity ions with a type opposite of that of the well area; and forming source and drain regions in the semiconductor substrate at both sides of the gate structure.