Details

Autor(en) / Beteiligte

• Kopas, Cameron J
• Goronzy, Dominic P
• Pham, Thang
• Torres Castanedo, Carlos G
• Cheng, Matthew
• Cochrane, Rory
• Nast, Patrick
• Lachman, Ella
• Zhelev, Nikolay Z
• Vallières, André
• Murthy, Akshay A
• Oh, Jin-su
• Zhou, Lin
• Kramer, Matthew J
• Cansizoglu, Hilal
• Bedzyk, Michael J
• Dravid, Vinayak P
• Romanenko, Alexander
• Grassellino, Anna
• Mutus, Josh Y
• Hersam, Mark C
• Yadavalli, Kameshwar

Titel

Enhanced superconducting qubit performance through ammonium fluoride etch

Ist Teil von

• Materials for quantum technology, 2024-12, Vol.4 (4), p.45101

Ort / Verlag

IOP Publishing

Erscheinungsjahr

2024

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• 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.