Fabrication of NbN/AlN superconducting multilayers

Abstract

Multilayers consisting of superconducting niobium nitride alternated with layers of insulating aluminum nitride have been fabricated using dc magnetron reactive sputtering. Under the proper conditions NbN can be produced in a (111) orientation and AlN in a (0001) orientation with an in-plane lattice mismatch of only 0.27%. Proper preparation of the aluminum target was necessary to ensure uniform deposition. X-ray diffraction and transmission electron microscopy verify the layered nature of these samples. Transport properties are studied as they relate to the structure of the system.