Qubit device, method for fabricating the qubit device, and contact layer for the method

A qubit device comprises first and second superconductor layers a capacitor, first and second interconnects. The first superconductor layer comprises a first c-axis perpendicular to covalently bound atomic layers. The second superconductor layer comprises a second c-axis perpendicular to covalently bound atomic layers. The first and second superconductor layers form a Josephson junction, wherein the first c-axis and the second c-axis are aligned with each other at the Josephson junction. The aligned first and second c-axes intersect both the first superconductor layer and the second superconductor layer. The capacitor comprises a first electrode and a second electrode. The first interconnect electrically connects the first electrode and the first superconductor layer. The second interconnect electrically connects the second electrode and the second superconductor layer. The capacitor is arranged at a vertical …