Some embodiments of the disclosure provide a semiconductor device. The semiconductor device includes: a doped substrate; a barrier layer, disposed on the doped substrate; a channel layer, disposed between the doped substrate and the barrier layer; and a doped semiconductor structure, disposed in the doped substrate, where a band gap of the barrier layer is greater than a band gap of the channel layer, the doped substrate and the doped semiconductor structure have different polarities, and the doped substrate includes a doped silicon substrate.