A semiconductor device includes a substrate, an epitaxial stack disposed on the substrate, a first connection layer between the epitaxial stack and the substrate and a first electrode disposed on the first connection layer. The substrate has a first side surface and a second side surface. The epitaxial stack has a semiconductor structure with a first lateral surface adjacent to the first side surface and a second lateral surface opposing the first lateral surface and adjacent to the second side surface. The first connection layer has a first protruding portion extending beyond the first lateral surface and a second protruding portion extending beyond the second lateral surface. The first electrode is in contact with the first protruding portion and the second protruding portion.