Investigation of the Mo and MoNx Thin Films for Superconducting Electronics Application

With the increase in integration and the layers of superconducting electronics circuits, molybdenum (Mo)-based films become attractive resistive and inductive functional components because of the large kinetic inductance with the deep magnetic field penetration depth. A DC magnetron sputtering technology is used to fabricate Mo and MoNx films. The effects of different deposition conditions on the electrical properties, topography and crystal structure of the films are investigated. For the Mo films, the resistivity and the surface roughness decrease to 193 nΩ m and 0.72 nm, respectively, as the sputtering power increases and the sputtering pressure is reduced. The dominant (110) peaks of the X-ray diffraction pattern show a blueshift, and the full width at half maximum decreases with the rising sputtering powers. For the MoNx films, the superconducting transition temperature firstly rises and then lowers as the ratio of N2/Ar ratio increases. The physical properties of the Mo and MoNx films change with the sputtering process, and suitable deposition conditions can be selected for the different application structures in the superconducting electronics circuits.