1. A superconducting integrated circuit, comprising: a first superconducting layer formed into a superconducting device, subject to alteration in superconducting device properties caused by at least hydrogen diffusion; a second superconducting layer having hydrogen diffused therein, providing a superconducting electronic path for communication with the first superconducting layer; and a diffusion barrier layer interposed between the first and second superconducting layers, formed from a composition which is superconductive or induced into superconductivity by proximity to the first and second superconducting layers, to thereby complete a non-switching superconducting path between the first and second superconducting layers, and which substantially blocks diffusion of hydrogen from the second superconducting layer to the first superconducting layer at temperatures below about 290K, such that the superconducting properties of the first superconducting layer remain stable after fabrication and storage at or below 290K, wherein the diffusion barrier layer is patterned together with the first superconducting layer in a common photolithographic mask step.