%0 Journal Article
%A Faley, M. I.
%A Fiadziushkin, Hleb
%A Frohn, Benedikt
%A Schüffelgen, P.
%A Dunin-Borkowski, R. E.
%T TiN nanobridge Josephson junctions and nanoSQUIDs on SiN-buffered Si
%J Superconductor science and technology
%V 35
%N 6
%@ 0953-2048
%C Bristol
%I IOP Publ.
%M FZJ-2022-01940
%P 065001 -
%D 2022
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000784122300001
%R 10.1088/1361-6668/ac64cd
%U https://juser.fz-juelich.de/record/907278