There is provided a semiconductor device including: a semiconductor element; a support substrate configured to support the semiconductor element; an intermediate metal layer interposed between the semiconductor element and the support substrate in a thickness direction of the support substrate, wherein the semiconductor element and the intermediate metal layer are bonded by solid phase diffusion bonding; and a first positioning portion including a portion of the semiconductor element and a first portion of the intermediate metal layer and configured to suppress relative movement between the semiconductor element and the intermediate metal layer.