The present disclosure teaches semiconductor devices and methods for manufacturing the same. Implementations of the semiconductor device may include: a semiconductor substrate; a semiconductor fin positioned on the semiconductor substrate; and a gate structure positioned on the semiconductor fin, where the gate structure includes a gate dielectric layer on a part of a surface of the semiconductor fin and a gate on the gate dielectric layer; where the gate includes a metal gate layer on the gate dielectric layer and a semiconductor layer on a side surface of at least one side of the metal gate layer; and where the semiconductor layer includes a dopant, where a conductivity type of the dopant is the opposite of a conductivity type of the semiconductor fin. The present disclosure can improve a work function of the device, thereby improving a current characteristic of the device during a working process, reducing the short channel effect (SCE), and lowering a leakage current.