Abstract: A system for incorporating superconductor circuits and semiconductor circuits in multilayered structures. A carrier material is chosen that is a good thermal match with the preferred superconductor substrates. The preferred superconductor substrate materials are lanthanum aluminate, magnesium oxide and neodymium gallate. The substrate carrier material should provide adequate thermal match through the range of operating temperatures which are preferably from room temperature to 77K. The preferred carrier material is a low temperature cofired ceramic (LTCC) which allows for multilayered structures to be developed which incorporate the superconductor circuitry and the semiconductor elements. The LTCC is composed of crystalline quartz particles in a borosilicate glass matrix. The percentage of quartz may be adjusted to adjust the thermal expansion characteristics of the LTCC.

Abstract: Disclosed is a superconducting Josephson junction which comprises a layer of niobium nitride on a substrate, an epitaxial layer of a pseudo-binary compound on the layer of niobium nitride, where the pseudo-binary compound has the composition about 3 atomic percent MgO--about 97 atomic percent CaO, to about 97 atomic percent MgO--about 3 atomic percent CaO, and an epitaxial layer of niobium nitride on the layer of pseudo-binary compound. Also disclosed is a method of making a Josephson junction by depositing a layer of niobium nitride onto a suitable substrate, depositing an expitaxial layer of a pseudo-binary compound onto the layer of niobium nitride, where the pseudo-binary compound has a composition of about 3 atomic percent MgO--about 97 atomic percent CaO, to about 97 atomic percent MgO--about 3 atomic percent CaO, and depositing an epitaxial layer of niobium nitride onto the layer said pseudo-binary compound.