Advances in Josephson Junction Materials and Processes Toward Practical Quantum Computing

The Josephson junction (JJ) is the fundamental nonlinear building block of superconducting quantum technologies. Its macroscopic quantum tunneling physics underpins superconducting quantum computing, sensing, and communication, but scaling these platforms to utility-scale architectures places increasingly stringent demands on junction materials, interfaces, and fabrication. Practical quantum computing requires high reproducibility, low power consumption, tunability, a small device footprint, and resilience to noise and defects. This review surveys how advances in materials science, device characterization, and nanofabrication are addressing these challenges and redefining the figures of merit for next-generation JJs. This review also examines the evolution of fabrication strategies, from conventional multi-angle evaporation to foundry-compatible superconducting processes and the integration of emerging junction materials. Progress along these directions will determine how rapidly JJs move from laboratory-scale components to the foundation of industrial-scale quantum processors.