Imec has demonstrated 3.8 million Josephson junctions per square centimeter and 30nm superconducting wiring, advancing scalable architectures for AI, HPC, quantum and photonic electronics.
Imec has demonstrated a new density milestone for superconducting integrated circuits, fabricating a three-metal-layer circuit with 3.8 million Josephson junctions per square centimeter. The development also includes superconducting niobium-titanium-nitride (NbTiN) wiring reduced to a 30nm linewidth, addressing a major scaling challenge for superconducting electronics. The results were presented at the 2026 Applied Superconductivity Conference.
The circuit platform uses NbTiN-based Josephson junctions, with junction diameters as small as 150nm. Josephson junctions act as extremely fast switching elements in superconducting logic, where information can be represented using quantized magnetic-flux pulses. Their combination of high switching speed and low energy dissipation makes superconducting logic attractive for compute-intensive electronics.
A key part of the development is the interconnect technology. Imec fabricated three layers of NbTiN routing containing wires and vias, with the smallest wires measuring only 30nm wide. This is approximately ten times narrower than conventional niobium-based superconducting wiring, allowing substantially more signal connections to be incorporated within a given chip area. The wiring can also support inductors, transmission lines, ground planes and clock or power resonators.
The platform is being developed using 300mm, CMOS-compatible semiconductor processes, providing a manufacturing route that is closer to established advanced-chip fabrication than conventional superconducting processes. Imec is also combining the technology with 2.5D and 3D heterogeneous integration, potentially allowing superconducting devices to be integrated with other semiconductor technologies.
The architecture is particularly relevant to AI accelerators and high-performance computing, where energy consumed moving data between processing elements has become a major system-level constraint. Superconducting interconnects can carry signals with extremely low electrical loss when operated below their superconducting transition temperature. Imec estimates that superconducting technology could eventually provide substantial advantages over CMOS in energy efficiency, compute density and bandwidth.
Beyond conventional computing, the same fabrication approach could support quantum-computing control electronics, photonic systems and neuromorphic processors. However, superconducting circuits still require cryogenic operation, creating additional cooling and system-integration requirements compared with conventional CMOS.
The 3.8-million-junction density and 30nm wiring therefore represent more than component miniaturization: they demonstrate a pathway toward making superconducting electronics denser and more compatible with modern semiconductor manufacturing.
