A superconductor device is manufactured by depositing a barrier layer over a substrate including silicon, the barrier layer including silicon and nitrogen; depositing a seed layer for a superconductor layer over the barrier layer, the seed layer including aluminum and nitrogen; depositing the superconductor layer over the seed layer, the superconductor layer including a layer of a superconductor material, the barrier layer serving as an oxidation barrier between the layer superconductor material and the substrate; and depositing a silicon cap layer over the superconductor layer. In some embodiments, the superconductor device includes a waveguide and a metal contact at a sufficient distance from the waveguide to prevent optical coupling between the metal contact and the waveguide.