Characterization of nitridized aluminium for quantum computing hardware applications

Abstract

Aluminium nitride (AlNx) has been exhaustively studied in the literature as an insulator displaying piezoelectricity. However, nitridized aluminium (NitrAl) in its metallic state has been recently identified to be a superconductor at low enough temperatures. NitrAl is of particular interest for superconducting quantum circuits due to showcasing great potential to achieve high kinetic inductance combined with low loss. In this project, NitrAl thin films have been fabricated in the regime of high kinetic inductance and characterized at cryogenic temperatures, completing in this way the investigation of its superconducting properties carried out by the IFAE QCT group. Furthermore, microwave resonators have been designed and analyzed to ascertain the actual value of the kinetic inductance of NitrAl and its changes with temperature