A semiconductor device is provided with a silicon layer, an upper surface side aluminum layer containing silicon and an insulation film. The upper surface side aluminum layer contacts and is layered on a part of a surface of the silicon layer. The insulation film contacts and is layered on another part of the surface of the silicon layer. The insulation film is adjacent to and contacts the upper surface side aluminum layer. The insulation film includes an insulation film body and a plurality of first nodule segregated portions projecting from the insulation film body toward the upper surface side aluminum layer as seen along a vertical direction relative to the surface of the silicon layer. A corner is formed by a side surface of the insulation film body and a side surface of each of the first nodule segregated portions as seen along the vertical direction.