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Advances in CMOS technology have enabled MOSFET with cutoff and maximum oscillation frequencies (ft and fmax) in the 400 GHz range, thus opening the path to CMOS-based applications at millimeter-wave (mm-wave) and sub-THz frequencies. Accurate compact models and therefore on-wafer MOSFET measurements at mm-wave frequencies and beyond become crucial for IC design at such high frequencies. However, accurate on-wafer measurement at these frequencies is a complex task requiring dedicating special care to calibration kit (calkit) design and characterization. This paper presents a complete and detailed parasitic correction procedure approach that demonstrates accurate corrected MOSFET measurements up to 110 GHz. It describes the custom calkit designed to perform ‘in-situ’ multiline Thru-Reflect-Line (mTRL) calibration. In this work, we compare different methods to evaluate the transmission line standards characteristic impedance and identify the best one by comparing the extracted series resistances of a MOSFET. The best method features frequency variations as low as

This review paper assesses the main approaches in the electrical characterization of advanced MOSFETs towards their future analog and RF applications. Those approaches are shown to be different from the traditionally used ones for the assessment of the device perspectives for digital applications. Based on the original research realized by our group over the last years, advantages and necessity of those techniques will be demonstrated on different study cases of various advanced MOSFETs, such as Fully Depleted Silicon-on-Insulator (FDSOI), FinFETs and NanoWires (NW) in a wide temperature range (from cryogenic, 4 K up to 250°C). A wide frequency band characterization (from DC up to hundred GHz range) will be positioned as a key element enabling a fair device assessment towards analog and RF applications. Importance of the “extrinsic” parasitic elements in the advanced devices is enormous, sometimes even dominating the device performance. Therefrom arises the need for a proper separate extraction and discussion of “intrinsic” versus “extrinsic” parameters.

This work presents a detailed RF characterization of 28-nm FD-SOI nMOSFETs at cryogenic temperatures down to 4.2 K. Two main RF Figures of Merit (FoMs), i.e., current-gain cutoff frequency (ft) and maximum oscillation frequency (fmax), as well as parasitic elements of the small-signal equivalent circuit, are extracted from the measured S-parameters. An improvement of up to ~130 GHz in ft and ~75 GHz in fmax is observed for the shortest device (25 nm) at low temperature. The behavior of RF FoMs versus temperature is discussed in terms of small-signal equivalent circuit elements, both intrinsic and extrinsic (parasitics). This study suggests 28-nm FD-SOI nMOSFETs as a good candidate for future cryogenic applications down to 4.2 K and clarifies the origin and limitations of the performance.

This work studies the self-heating (SH) effect in ultra-thin body ultra-thin buried oxide (UTBB) FDSOI MOSFETs at cryogenic temperatures down to 77 K. S-parameter measurements in a wide frequency range, with the so-called RF technique, are employed to assess SH parameters and related variation of analog figures of merit (FoMs) at different temperatures. Contrary to the expectations, the effect of self-heating on analog FoMs is slightly weaker at cryogenic temperatures with respect to room-temperature case. The extracted thermal resistance and channel temperature rise at 300 K and 77 K in short-channel devices are of the same order of magnitude. The observed increase in SH characteristic frequency with temperature reduction emphasizes the advantage of the RF technique for the fair analysis of SH-related features in advanced technologies at cryogenic temperatures.

In this paper, measurements and simulations of miniature monopole antennas for ultra-wideband (UWB) GHz intra- and inter-chips communication and biomedical applications are presented. Folded designs on four substrates are studied: 1) standard bulk; 2) high-resistivity bulk; 3) ultra low-loss radiofrequency silicon-on-insulator (RF SOI); and 4) quartz. Among the Si-based substrates, RF SOI with its trap-rich sublayer demonstrates the best performances with the lowest RF power losses and centimetric transmission distance between antennas. Transmitted power between two antennas was measured from 0.01 to 20 GHz. Using substrate characterization of resistivity, permittivity, and loss tangent based on measured coplanar waveguide lines on the same substrates, good agreement is obtained between the return losses of simulated antennas on each substrate and numerical solutions, confirming the impact of the substrate properties. An antenna bandwidth of 680 MHz is demonstrated at 6.0 GHz meeting the criterion for UWB radio communications in the 6-10 GHz band.

How to select cases in social innovation research? Sampling units of analysis is indeed a challenging methodological question since social innovation theory is controversial and fragmented. In the absence of any database and given the limits of conventional techniques, sampling is only possible through participative methods that make sense of opposing perceptions and contestedness. This article presents the Delphi method and its related principles of expertise, iterative consultation and consensus forming and shows how it served to identify a pool of cases of social innovation, sort them out and finally establish a sample of social innovations in a partnership research on innovative practices in domiciliary eldercare.