A metal-oxide semiconductor transistor includes a substrate, a gate insulating layer disposed on a surface of the substrate, and a metal gate disposed on the gate insulating layer, wherein at least one of the length or the width of the metal gate is greater than or equal to approximately 320 nanometers, and the metal gate has at least one plug hole. The metal-oxide semiconductor transistor further includes at least one insulating plug disposed in the plug hole and two diffusion regions disposed respectively at two sides of the metal gate in the substrate.