Enhanced superconducting qubit performance through ammonium fluoride etch
Year: 2024
Type: article
Abstract: The performance of superconducting qubits is often limited by dissipation and two-level systems (TLS) losses. The dominant sources of these losses are believed to originate from amorphous materials and defects at interfaces and surfaces, likely as a result of fabrication processes or ambient exposure. Here, we explore a novel wet chemical surface treatment at the Josephson junction-substrate and the substrate-air interfaces by replacing a buffered oxide etch (BOE) cleaning process with one that uses hydrofluoric acid followed by aqueous ammonium fluoride. We show that the ammonium fluoride etch process results in a statistically significant improvement in median T 1 by ∼ 22 % (p = 0.002), and a reduction in the number of strongly-coupled TLS in the tunable frequency range. Microwave resonator measurements on samples treated with the ammonium fluoride etch after niobium deposition and etching also show ∼ 33 % lower TLS-induced loss tangent compared to the BOE treated samples. As the chemical treatment primarily modifies the Josephson junction-substrate interface and substrate-air interface, we perform targeted chemical and structural characterizations to examine materials differences at these interfaces and identify multiple microscopic changes that could contribute to decreased TLS losses.
Source: Materials for Quantum Technology
Authors: Cameron J Kopas, Dominic P Goronzy, Thang Pham, Carlos G Torres Castanedo, Matthew Cheng, Rory Cochrane, Patrick Nast, Ella Lachman, Nikolay Z Zhelev, André Vallières, Akshay A Murthy, Jin-su Oh, Lin Zhou, Matthew J Kramer, Hilal Cansizoglu, Michael J Bedzyk, Vinayak P Dravid, Alexander Romanenko, Anna Grassellino, Josh Y Mutus, Mark C Hersam, Kameshwar Yadavalli
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,565
Funders: National Science Foundation, U.S. Department of Energy, Northwestern University, Iowa State University, Office of Science, Materials Research Science and Engineering Center, Harvard University, Materials Research Science and Engineering Center, Northwestern University, Division of Materials Research, Division of Electrical, Communications and Cyber Systems
Awards: NNCI: Soft Hybrid Nanotechnology Experimental (SHyNE) Resource, G1418315740, G1519358529, G1866217153, G2233802770, G2248407278, G2343375527, G2441759041, G249831736, G3010471893, G3203750490, Northwestern University Materials Research Science and Engineering Center, G4958141111, G498139845, G524707868, G5616713406, G585908603, G5959670421, G6540817556, G716412294, G86560745, G969889393
OpenAlex ID: W4403528020