A semiconductor device includes an active region, including: a semiconductor layer, having a first surface, including a collector layer, a base layer and an emitter layer sequentially stacked, and the first surface being a surface of the emitter layer facing away from the base layer; an emitter mesa and an emitter electrode sequentially disposed on the emitter layer; a first dielectric layer, covering a top surface of the emitter electrode, extending along a side surface of the emitter electrode to cover part of the first surface exposed outside the emitter electrode, and defining a first opening; a second dielectric layer, covering the first dielectric layer, and defining a second opening connected to the first opening; and a base electrode, connected to the base layer through the first opening and the second opening, and extending to cover at least part of the second dielectric layer adjacent to the second opening.