Planarized Structure for Josephson Tunnel Junctions
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-02
The proposed Josephson junction structures are formed in a sandwich layer of alternate films of superconducting and insulating material deposited on a substrate (Fig. A). The fabrication process then comprises the steps of (1) etching a hole into the sandwich layer (Fig. B), (2) formation of tunnel oxides for junctions J1 and J2, (3) deposition of a superconducting bridge S3 (Fig. C), and (4) planarization (Figs. D and E). The homogeneous sandwich films and the absence of photoresist patterns during the formation of the tunnel barrier result in good uniformity of the junctions. The fabrication steps are illustrated in Figs. A-E. Initially, a uniform sandwich of alternate films of, e.g., NB (S1, S2) and Si (I1, I2), each about 2000 ˜ in thickness, is formed on an underlying substrate.