A scalable non-superconducting tunnel junction technology
Abstract
Tunnel junctions are one of the key elements of chip-scale microsystems serving various technologies from classical microelectronics to quantum information. Aluminium and its oxide (AlOx) have dominated cryogenic tunnel junction technology for decades due to the high quality of AlOx barriers and Al superconducting properties below 1.2 K. However, many applications require non-superconducting junctions, either standalone or in combination with superconducting technology, motivating efforts to suppress Al superconductivity through magnetic fields, doping, or proximity effects -- approaches that so far suffered from integration compatibility and scalability issues. Here, we present a CMOS-compatible normal-metal tunnel junction technology based on TiW alloy and AlOx barriers. We demonstrate wafer-scale fabrication of TiW/Al-AlOx/TiW junctions and validate their performance in Coulomb blockade thermometers operating down to 20 mK, confirming robust normal-state behavior. This TiW-based architecture offers a scalable solution for non-superconducting tunnel junctions across a broad temperature range, enabling integration into advanced cryogenic, quantum and nanoelectronic chip-level systems.
Keywords
Cite
@article{arxiv.2602.14637,
title = {A scalable non-superconducting tunnel junction technology},
author = {Juho Luomahaara and Kristupas Razas and Omid Sharifi Sedeh and Renan P. Loreto and Janne S. Lehtinen and Mingchi Xu and Armel A. Cotten and Aldo Tarascio and Peter Müller and Nikolai Yurttagül and Lassi Lehtisyrjä and Leif Grönberg and Christian P. Scheller and Jonathan R. Prance and Michael D. Thompson and Richard P. Haley and Mika Prunnila and Dominik M. Zumbühl},
journal= {arXiv preprint arXiv:2602.14637},
year = {2026}
}
Comments
9 pages, 6 figures; equal contribution of J.L., K.R., O.S.S, and R.P.L