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Extremely scaled down tri-gate RF metal-oxide-semiconductor fieldeffect transistors (MOSFETs) utilising lateral nanowires as the channel, with gate length and nanowire width both of 20 nm are reported. These devices exhibit simultaneous extrapolated ft and fmax of 275 and 400 GHz at VDS = 0.5 V, which is the largest combined ft and fmax, as well as the largest fmax reported for all III-V MOSFETs. [ABSTRACT FROM AUTHOR]

Weyl semimetals are defined by their unique Fermi surface, comprising pairs of Weyl points of opposite chirality, connected through topological surface states. Angle-resolved photoemission spectroscopy (ARPES) has been used to verify the existence of the Weyl points and the Fermi arcs. However, ARPES is limited in resolution, leading to significant uncertainty when characterizing the shape of the Fermi surface of semimetals and measuring features such as the distance between the Weyl points. Here, to surpass the resolution of ARPES, we combine quantum oscillation measurements with transverse electron focusing experiments. These techniques offer complementary information, enabling the reconstruction of the distinctive peanut-shaped cross section of the Weyl Fermi surface and accurately determining the separation between Weyl points in the Weyl semimetal NbP. Our Letter showcases the integration of quantum oscillations and transverse electron focusing, allowing for the measurements of complex Fermi surface geometries, concurrently with carriers' transport properties, in high-mobility quantum materials.

In recent times the chiral semimetal cobalt monosilicide (CoSi) has emerged as a prototypical, nearly ideal topological conductor hosting giant, topologically protected Fermi arcs. Exotic topological quantum properties have already been identified in CoSi bulk single crystals. However, CoSi is also known for being prone to intrinsic disorder and inhomogeneities, which, despite topological protection, risk jeopardizing its topological transport features. Alternatively, topology may be stabilized by disorder, suggesting the tantalizing possibility of an amorphous variant of a topological metal, yet to be discovered. In this respect, understanding how microstructure and stoichiometry affect magnetotransport properties is of pivotal importance, particularly in case of low-dimensional CoSi thin films and devices. Here we comprehensively investigate the magnetotransport and magnetic properties of ≈25 nm Co 1- x Si x thin films grown on a MgO substrate with controlled film microstructure (amorphous vs textured) and chemical composition (0.40 < x < 0.60). The resistivity of Co 1- x Si x thin films is nearly insensitive to the film microstructure and displays a progressive evolution from metallic-like (dρ xx /d T > 0) to semiconducting-like (dρ xx /d T < 0) regimes of conduction upon increasing the silicon content. A variety of anomalies in the magnetotransport properties, comprising for instance signatures consistent with quantum localization and electron-electron interactions, anomalous Hall and Kondo effects, and the occurrence of magnetic exchange interactions, are attributable to the prominent influence of intrinsic structural and chemical disorder. Our systematic survey brings to attention the complexity and the challenges involved in the prospective exploitation of the topological chiral semimetal CoSi in nanoscale thin films and devices., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

III-V semiconductors are being considered as promising candidates to replace silicon channel for low-power logic and RF applications in advanced technology nodes. InGaAs is particularly suitable as the channel material in n-type metal-oxide-semiconductor field-effect transistors (MOSFETs), due to its high electron mobility. In the present work, we report on InGaAs FinFETs monolithically integrated on silicon substrates. The InGaAs channels are created by metal⁻organic chemical vapor deposition (MOCVD) epitaxial growth within oxide cavities, a technique referred to as template-assisted selective epitaxy (TASE), which allows for the local integration of different III-V semiconductors on silicon. FinFETs with a gate length down to 20nm are fabricated based on a CMOS-compatible replacement-metal-gate process flow. This includes self-aligned source-drain n⁺ InGaAs regrown contacts as well as 4 nm source-drain spacers for gate-contacts isolation. The InGaAs material was examined by scanning transmission electron microscopy (STEM) and the epitaxial structures showed good crystal quality. Furthermore, we demonstrate a controlled InGaAs digital etching process to create doped extensions underneath the source-drain spacer regions. We report a device with gate length of 90 nm and fin width of 40 nm showing on-current of 100 µA/µm and subthreshold slope of about 85 mV/dec.