The present invention discloses a semiconductor device, comprising: a substrate, a gate stack structure on the substrate, source and drain regions in the substrate on both sides of the gate stack structure, and a channel region between the source and drain regions in the substrate, characterized in that the source region in the source and drain regions comprises GeSn alloy, and a tunnel dielectric layer is optionally comprised between the GeSn alloy of the source region and the channel region. In accordance with the semiconductor device and method for manufacturing the same of the present invention, GeSn alloy having a narrow band gap is formed by implanting precursors and performing a laser rapid annealing, the on-state current of TFET is effectively enhanced, accordingly it has an important application prospect in a high performance low power consumption application.