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The scalability of the quantum processor technology is elemental in reaching fault-tolerant quantum computing. Owing to the maturity of silicon microelectronics, quantum bits (qubits) realized with spins in silicon quantum dots are considered among the most promising technologies for building scalable quantum computers. However, to realize quantum-dot-based high-fidelity quantum processing units several challenges need to be solved. In this respect, improving the charge noise environment of silicon quantum dot-based qubits and the development of ultra-low-power on-chip cryogenic classical complementary metal oxide semiconductor (CMOS) electronics for the manipulation and interfacing of the qubits are important milestones. We report scalable interfacing of highly tunable and ultra-low charge noise electron and hole quantum dots embedded in a 64-channel cryogenic CMOS multiplexer, which has less-than-detectable static power dissipation (< 1 pW) even at sub-1 K temperatures. Our integrated hybrid quantum-dot CMOS technology provides a route to scalable interfacing of up to millions of high-quality quantum dots enabling, for example, straightforward variability analysis and qubit geometry optimization, which are essential prerequisites for building fault-tolerant large-scale silicon-based quantum computers. At 5.6 K temperature, we find unprecedentedly low charge noise of 22 and 28 $μ$eV/$\sqrt {Hz}$ at 1 Hz in the electrostatically defined few-electron and few-hole quantum dots, respectively. The low-noise quantum dots are realized by harnessing a custom CMOS process that utilizes a conventional doped-Poly-Si/SiO$_2$/Si MOS stack. This approach provides lower charge noise background than high-k metal gate solutions and translates into higher spin qubit fidelities., 13 pages, 4 figures, 7 extended data figures, 11 supplementary figures

Funding Information: E. Österlund appreciates the funding from the European Space Agency (NPI Grant No. 4000116390) and Aalto ELEC Doctoral School. Dr. Žukauskaitė appreciates the funding from FhG Internal Programs under Grant No. Attract 005-600636. Dr. Vesa Vuorinen and Dr. Hongqun Dong are acknowledged for useful discussions. This research was conducted as a part of the EU project POSITION II (Ecsel-783132-Position-II-2017-IA) and performed partly at the Aalto University OtaNano–Micronova Nanofabrication Centre and Nanomicroscopy Center. Publisher Copyright: © 2021 authors. Published by the American Physical Society. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. | openaire: EC/H2020/783132/EU//POSITION-II Scandium-alloying of aluminum nitride (AlScN) enhances the piezoelectric properties of the material and increases the performance of piezoelectric microelectromechanical systems (MEMS). However, this enhancement is caused by the destabilization of the wurtzite phase and so far the stability of AlScN thin films has not been sufficiently studied. Stability is especially important for piezoelectric devices because changes to the film microstructure or residual stress can lead to drastic changes in the device behavior. The stability of AlScN is investigated by annealing sputtered films and characterizing the resulting changes. It is found that the wurtzite phase of Al0.7Sc0.3N is stable at least up to 1000∘C and annealing increases the crystal quality, reaching a maximum at 800∘C. When annealed for more than 100 h at 1000∘C, argon used in sputtering segregates into the grain boundaries and causes compressive strains and formation of rock-salt phase. Additionally, annealing at 1000∘C for 5 h reduces the average tensile stress by approximately 1 GPa.

A sensor (1) comprises a transducer (2), a base plate (3) comprising a space (4) for accommodating the transducer (2), and a silicon-on-insulator plate (5) on top of the base plate (3). The base plate (3) forms a frame for the transducer (2) and the silicon-on-insulator plate (5) at least partly defines a horizontally and vertically extending cavity (6) arranged in connection with the transducer (2). The sensor (1) further comprises a top element (7) on top of the silicon-on-insulator plate (5) for terminating the cavity (6).Patent family as of 17.12.2021EP3545294 A1 20191002 EP20170811345 20171123 FI127836 B 20190329 FI20160005894 20161124 FI20165894 A 20180525 FI20160005894 20161124 FI20165894 L 20180525 FI20160005894 20161124 US2019346409 AA 20191114 US20170461521 20171123 WO18096216 A1 20180531 WO2017FI50816 20171123Link to current patent family on right

A capacitive pressure sensor for an internal combustion engine is provided having a housing having a bottom surface, variable capacitor and circuitry. The variable capacitor is formed by a stationary electrode and an elastically bendable electrode. Pressure exerted on the bottom surface acts to bend the elastically bendable electrode. This bending alters the capacitance of the variable capacitor. The circuitry is configured to generate a signal based on the variable capacitance of the variable capacitor. This capacitance is representative of the pressure exerted on the bottom surface.Patent family as of 8.12.2021CN107923810 A 20180417 CN201680050824 20160719 CN107923810 B 20200519 CN201680050824 20160719 EP3325932 A1 20180530 EP20160739512 20160719 JP2018521325 T2 20180802 JP20180503242T 20160719 JP6681972 B2 20200415 JP20180503242T 20160719 US10139313 BB 20181127 US20150805478 20150722 US2017023440 AA 20170126 US20150805478 20150722 WO17013109 A1 20170126 WO2016EP67161 20160719 WO17013109 A8 20170316 WO2016EP67161 20160719Link to currentpatent family on right

This thesis concentrates on studies of AlOx based tunnel junctions and their feasibility for cooling, thermometry and strain sensing in suspended nanostructures. The main result of the thesis is cooling of one dimensional phonon modes of a suspended nanowire with normal metal insulator superconductor (NIS) tunnel junctions. Simultaneous cooling of both electrons and phonons was achieved, and the lowest phonon temperature reached in the system was 42 mK with an initial temperature of 100 mK. In addition, suspended devices show cooling still at a bath temperature of 600 mK. The observed thermal transport characteristics show, that the heat flow is limited by the scattering of phonons at the bulk nanowire interface. The properties of Al AlOx Al tunnel junctions can be improved by thermal annealing in vacuum at 350 450 C. Annealing treatment will lead to complete stabilization of the junctions, and on increase in both tunneling resistance and charging energy. In addition, the annealing process shows a marked improvement in the tunneling conductance spectrum, indicated by a disappearance of several resonances, which are a fingerprint of either resonant or inelastic tunneling processes caused typically by impurities located in the tunneling barrier. The superconducting gap of Al is not affected, but the supercurrent is reduced, consistent with the increase of tunneling resistance. Feasiblity of conventional, sub micron sized Al AlOx Al tunnel junctions in sensing strain, and therefore displacement, is demonstrated in the final chapter of this thesis. Tunnel junctions show a good response to applied strain (gauge factor), which is competitive with existing strain and displacement detectors.