Abstract: A metal-oxide-semiconductor field-effect transistor (MOSFET) and a method for fabricating the MOSFET are disclosed. In the method, after a gate is formed by etching a deposited undoped or lightly-doped polysilicon layer, with the portions of the gate above channel edge between a channel region and STI region being protected, ions are doped into the remaining gate portion during source/drain implantation. As a result, each of the gate portions above channel edge is constructed of a doped second polysilicon layer stacked with undoped (or lightly-doped) first polysilicon layers, while the remaining gate portion is simply constituted by the doped second polysilicon layer. This can increase a threshold voltage of the MOSFET at channel edge. Optionally, before the gate is formed by etching the polysilicon, the portions of the polysilicon above the channel edge may be protected, followed by doping ions into the remaining portions of the polysilicon.