Qubit-Compatible Substrates With Superconducting Through-Silicon Vias
Kestutis Grigoras, Nikolai Yurttagül, J.-P. Kaikkonen, E. T. Mannila, Patrik Eskelinen, Daniel Pérez Lozano, Hang-Xi Li, Mathias Rommel, Daryoush Shiri, Nils Tiencken, Slawomir Simbierowicz, Alberto Ronzani, Joel Hätinen, Debopam Datta, Visa Vesterinen, Leif Grönberg, Janka Biznárová, Anita Fadavi Roudsari, Sandoko Kosen, Amr Osman, M. Prunnila, Juha Hassel, Jonas Bylander, Joonas Govenius
Abstract
We fabricate and characterize superconducting through-silicon vias and electrodes suitable for superconducting quantum processors. We measure internal quality factors of a million for test resonators excited at single-photon levels, on chips with superconducting vias used to stitch ground planes on the front and back sides of the chips. This resonator performance is on par with the state of the art for silicon-based planar solutions, despite the presence of vias. Via stitching of ground planes is an important enabling technology for increasing the physical size of quantum processor chips, and is a first step toward more complex quantum devices with three-dimensional integration.