Semiconductor device and manufacturing method thereof

The invention discloses a semiconductor device and a manufacturing method thereof. The semiconductor device comprises a III-V compound semiconductor layer, a silicon-doped III-V compound barrier layer and a silicon-rich tensile stress layer. A silicon-doped III-V compound barrier layer is disposed on the III-V compound semiconductor layer, and a silicon-rich tensile stress layer is disposed on the silicon-doped III-V compound barrier layer. The manufacturing method of the semiconductor device comprises the following steps. A group III-V compound barrier layer is formed on the group III-V compound semiconductor layer. And forming a silicon-rich tensile stress layer on the III-V group compound barrier layer. And after the silicon-rich tensile stress layer is formed, performing an annealing manufacturing process. A portion of silicon in the silicon-rich tensile stress layer is diffused into the III-V compound barrier layer through an annealing fabrication process to form a silicon-doped III-V compound barrier la