Journal Article

FZJ-2022-01940

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png TiN nanobridge Josephson junctions and nanoSQUIDs on SiN-buffered Si

Faley, M. I. (Corresponding author)FZJ* ; Fiadziushkin, H.FZJ* ; Frohn, B.FZJ* ; Schüffelgen, P.FZJ* ; Dunin-Borkowski, R. E.FZJ*

2022
IOP Publ. Bristol

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Please use a persistent id in citations: http://hdl.handle.net/2128/31046  doi:10.1088/1361-6668/ac64cd

Abstract: We report the fabrication and properties of titanium nitride (TiN) nanobridge Josephson junctions (nJJs) and nanoscale superconducting quantum interference devices (nanoSQUIDs) on SiN-buffered Si substrates. The superior corrosion resistance, large coherence length, suitable superconducting transition temperature and highly selective reactive ion etching (RIE) of TiN compared to e-beam resists and the SiN buffer layer allow for reproducible preparation and result in long-term stability of the TiN nJJs. High-resolution transmission electron microscopy reveals a columnar structure of the TiN film on an amorphous SiN buffer layer. High-resolution scanning electron microscopy reveals the variable thickness shape of the nJJs. A combination of wet etching in 20% potassium hydroxide and RIE is used for bulk nanomachining of nanoSQUID cantilevers. More than 20 oscillations of the V(B) dependence of the nanoSQUIDs with a period of ∼6 mT and hysteresis-free I(V) characteristics (CVCs) of the all-TiN nJJs are observed at 4.2 K. CVCs of the low-Ic all-TiN nJJs follow theoretical predictions for dirty superconductors down to ∼10 mK, with the critical current saturated below ∼0.6 K. These results pave the way for superconducting electronics based on nJJs operating non-hysteretically at 4.2 K, as well as for all-TiN qubits operating at sub-100 mK temperatures.

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Contributing Institute(s):

1. Physik Nanoskaliger Systeme (ER-C-1)
2. Halbleiter-Nanoelektronik (PGI-9)

Research Program(s):

1. 5351 - Platform for Correlative, In Situ and Operando Characterization (POF4-535) (POF4-535)
2. 5222 - Exploratory Qubits (POF4-522) (POF4-522)

Appears in the scientific report 2022

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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