The present invention discloses a semiconductor device, comprising: a substrate, a channel layer epitaxially grown in the substrate, a gate stack structure on the channel layer, gate spacers on both sides of the gate stack structure, and source / drain areas on both sides of the channel layer in the substrate, characterized in that the carrier mobility of the channel layer is higher than that of the substrate. In accordance with the semiconductor device and the method of manufacturing the same in the present invention, forming the device channel region by filling the trench with epitaxial high-mobility materials in a gate last process can enhance the carrier mobility in the channel region, thereby the device response speed is substantially improved and the device performance is greatly enhanced. Furthermore, traditional materials for a substrate are still used for the source / drain areas of the device to facilitate usage of a gate last process, thereby enhancing the performance while reducing the cost at the same time.