Abstract: A method for fabricating a semiconductor device includes: providing a substrate layer stack including a substrate with a metallic upper surface, a first Ni containing layer disposed on the substrate, and a first Sn layer on the first Ni containing layer; depositing a first semiconductor layer stack on the first Sn layer and that includes a first NiP layer, a first semiconductor die disposed on the first NiP layer, and a second NiP layer disposed on the first semiconductor die; depositing a second semiconductor layer stack on the first semiconductor layer stack and that includes a second Sn layer, a second Ni containing layer disposed on the second Sn layer, and a second semiconductor die disposed on the second Ni containing layer; and performing a diffusion soldering process for connecting the first semiconductor layer stack to the substrate and the second semiconductor layer stack to the first semiconductor layer stack.