6 research outputs found
Superconducting routing platform for large-scale integration of quantum technologies
To reach large-scale quantum computing, three-dimensional integration of
scalable qubit arrays and their control electronics in multi-chip assemblies is
promising. Within these assemblies, the use of superconducting
interconnections, as routing layers, offers interesting perspective in terms of
(1) thermal management to protect the qubits from control electronics
self-heating, (2) passive device performance with significant increase of
quality factors and (3) density rise of low and high frequency signals thanks
to minimal dispersion. We report on the fabrication, using 200 mm silicon wafer
technologies, of a multi-layer routing platform designed for the hybridization
of spin qubit and control electronics chips. A routing level couples the qubits
and the control circuits through one layer of Al0.995Cu0.005 and
superconducting layers of TiN, Nb or NbN, connected between them by W-based
vias. Wafer-level parametric tests at 300 K validate the yield of these
technologies and low temperature electrical measurements in cryostat are used
to extract the superconducting properties of the routing layers. Preliminary
low temperature radio-frequency characterizations of superconducting passive
elements, embedded in these routing levels, are presented
NbN-on-Si superconducting nanowire single photon detectors: effect of a sputtered AlN buffer layer
International audienc
NbN-on-Si superconducting nanowire single photon detectors: effect of a sputtered AlN buffer layer
International audienc
Improvement of critical temperature of niobium nitride deposited on 8-inch silicon wafers thanks to an AlN buffer layer
International audienceIn this paper, we study the crystalline properties and semiconducting critical temperature of ultra-thin (5-9 nm) NbN films deposited on 8-inch silicon wafers by reactive sputtering. We show that the deposition of NbN on a thin (10-20 nm) AlN buffer layer, also synthesized by reactive sputtering, improves the critical temperature by several Kelvin, up to 10 K for 9 nm NbN on 20 nm AlN. We correlate this improvement to the higher-crystalline quality of NbN on AlN. While NbN deposited directly on silicon is polycrystalline with randomly oriented grains, NbN on AlN(0001) is textured along (111), due to the close lattice match. The superconducting properties of the NbN/AlN stack are validated by the demonstration of fiber-coupled normal-incidence superconducting nanowire single photon detectors. The whole fabrication process is CMOS compatible, with a thermal budget compatible with the integration of other passive and active components on silicon. These results pave the way for the integration of a large number of surface or waveguide-integrated detectors on large-scale silicon wafers. Furthermore, as AlN is transparent over a broad wavelength range from the visible to the near-infrared, the optimized superconducting NbN/AlN stack can be used for a wide variety of applications, from imaging to quantum communications and quantum computing