Provided is a semiconductor device including a substrate, a semiconductor layer, a source electrode, a first metal layer, a backside via hole, and a backside metal layer. The substrate has a frontside and a backside opposite to each other. The semiconductor layer is disposed on the frontside of the substrate. The source electrode is disposed on the semiconductor layer. The first metal layer is disposed on the source electrode. The backside via hole extends from the backside of the substrate to a bottom surface of the first metal layer. The backside via hole is laterally separated from the source electrode by a non-zero distance. The backside metal layer is disposed on the backside of the substrate and extending to cover a surface of the backside via hole.