V TH -Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate

International audienceThis paper contributes to investigations on the threshold-voltage (VTH) hysteresis in SiC power MOSFETs. Such effect is of relevance mainly for sub-threshold operation of the devices, but needs to be told apart from stress-related VTH-drift phenomena for technology maturity and reliability validation goals. Important differences exist in commercially available devices, particularly in relation to their gate technology, planar or trench, the latter also showing a marked temperature dependence of the hysteretic range. Based on the experimental characterization of the interface capacitance and charge, this paper puts forward a methodology for determining the types of traps affecting the various devices, with the aim of contributing a tool to assist driving of technological maturity in future generation devices. This paper also shows the potential of capacitance hysteresis measurement to the estimation of the distribution of interface

Switchable Brønsted acid-catalyzed ring contraction of Cyclooctatetraene oxide towards the enantioselective synthesis of Cyloheptatrienyl-substituted homoallylic Alcohols and Oxaborinanes

The ability of cyclooctatetraene oxide to undergo two sequential ring contraction events under mild conditions, using Brønsted acid catalysis, has been studied in detail. We have found that the selectivity can be controlled by the acidity of the catalyst and by the temperature, being able to obtain selectively either the cycloheptatriene carbaldehyde product, arising from a single ring-contraction event, or phenylacetaldehyde that is formed after a second ring contraction process. A complete mechanistic picture of the reaction and a rationale behind the influence of the catalyst is provided based on both experimental and computational data. Finally, this acid-catalyzed ring contraction has been coupled with an in situ enantioselective allylation reaction, delivering enantioenriched cycloheptatrienyl-substituted homoallylic alcohols when it is carried out in the presence of a chiral phosphoric acid catalyst. These homoallylic alcohols have also been converted into enantioenriched oxaborinanes through copper-catalyzed nucleophilic borylation/cyclization protocol

Design of a Low-Capacitance Planar Transformer for a 4 kW/500 kHz DAB Converter

International audienceIncreasing electrification in transport sectors, from automotive to aerospace, highlights the need for low size and high power density components. The recent advent of planar technology theoretically allows to reduce considerably the size of the magnetic components. This article focuses on the design of a high frequency planar transformer intended to be used in a 4 kW 500 kHz DAB converter. In particular, the inter-winding capacitances are assessed, as they have a strong influence on the behaviour of the DAB, and in some extreme cases may impede operation entirely. Analytical and finite element models are used to evaluate the stray elements of the transformer (resistance of the conductors, inter-winding capacitance and leakage inductance), and the resulting circuit model is compared with experimental measurements. This work focuses on influences of design parameters on the transformer stray elements

Future-ai:International consensus guideline for trustworthy and deployable artificial intelligence in healthcare

Despite major advances in artificial intelligence (AI) for medicine and healthcare, the deployment and adoption of AI technologies remain limited in real-world clinical practice. In recent years, concerns have been raised about the technical, clinical, ethical and legal risks associated with medical AI. To increase real world adoption, it is essential that medical AI tools are trusted and accepted by patients, clinicians, health organisations and authorities. This work describes the FUTURE-AI guideline as the first international consensus framework for guiding the development and deployment of trustworthy AI tools in healthcare. The FUTURE-AI consortium was founded in 2021 and currently comprises 118 inter-disciplinary experts from 51 countries representing all continents, including AI scientists, clinicians, ethicists, and social scientists. Over a two-year period, the consortium defined guiding principles and best practices for trustworthy AI through an iterative process comprising an in-depth literature review, a modified Delphi survey, and online consensus meetings. The FUTURE-AI framework was established based on 6 guiding principles for trustworthy AI in healthcare, i.e. Fairness, Universality, Traceability, Usability, Robustness and Explainability. Through consensus, a set of 28 best practices were defined, addressing technical, clinical, legal and socio-ethical dimensions. The recommendations cover the entire lifecycle of medical AI, from design, development and validation to regulation, deployment, and monitoring. FUTURE-AI is a risk-informed, assumption-free guideline which provides a structured approach for constructing medical AI tools that will be trusted, deployed and adopted in real-world practice. Researchers are encouraged to take the recommendations into account in proof-of-concept stages to facilitate future translation towards clinical practice of medical AI

FUTURE-AI: International consensus guideline for trustworthy and deployable artificial intelligence in healthcare

Despite major advances in artificial intelligence (AI) for medicine and healthcare, the deployment and adoption of AI technologies remain limited in real-world clinical practice. In recent years, concerns have been raised about the technical, clinical, ethical and legal risks associated with medical AI. To increase real world adoption, it is essential that medical AI tools are trusted and accepted by patients, clinicians, health organisations and authorities. This work describes the FUTURE-AI guideline as the first international consensus framework for guiding the development and deployment of trustworthy AI tools in healthcare. The FUTURE-AI consortium was founded in 2021 and currently comprises 118 inter-disciplinary experts from 51 countries representing all continents, including AI scientists, clinicians, ethicists, and social scientists. Over a two-year period, the consortium defined guiding principles and best practices for trustworthy AI through an iterative process comprising an in-depth literature review, a modified Delphi survey, and online consensus meetings. The FUTURE-AI framework was established based on 6 guiding principles for trustworthy AI in healthcare, i.e. Fairness, Universality, Traceability, Usability, Robustness and Explainability. Through consensus, a set of 28 best practices were defined, addressing technical, clinical, legal and socio-ethical dimensions. The recommendations cover the entire lifecycle of medical AI, from design, development and validation to regulation, deployment, and monitoring. FUTURE-AI is a risk-informed, assumption-free guideline which provides a structured approach for constructing medical AI tools that will be trusted, deployed and adopted in real-world practice. Researchers are encouraged to take the recommendations into account in proof-of-concept stages to facilitate future translation towards clinical practice of medical AI

Transition metal and radical free 1,2-dicarbofunctionalisation of 1,1-arylboryl alkenes through dual C(sp3)-C(sp3) bond formation

We reveal here the regioselective nucleophilic addition of C(sp3) to 1,1-arylboryl alkenes, followed by nucleophilic attack of the alpha-boryl carbanionic intermediates to C(sp3) electrophiles, at room temperature. We envisioned this goal through engaged C(sp3) chemical entities avoiding metal catalysts, additives, radical initiators or specific irradiation. This multicomponent reaction guarantees that the new tetrasubstituted carbon formed retains all the C atoms from the three starting materials involved in the assembly

Étude de la robustesse de l’oxyde de grille pour des applications aéronautiques

National audienceAeronautics industry is working towards a more electrified aircraft. That represents a challenge and involves the use of new technologies as silicon carbide (SiC) for the conception of MOSFET transistors. However, this technology presents some reliability problems as short-circuit and avalanche mode robustness as well as the threshold voltage instability and gate oxide reliability. This paper presents the principal issues on SiC MOSFETs reliability, as well as a study of threshold voltage instability and gate oxide reliability. The results presented in this paper will show that gate oxide reliability problems have been dramatically reduced. However, it remains some voltage threshold instability when internal diode is required. Concerning the gate oxide robustness, it is possible to conclude that SiC MOSFETs are relatively reliable for industrial applications.MOTS-CLESDans la cadre d’un avion plus électrique, de nouveaux défis se présentent. Parmi eux, l’évaluation de nouvelles technologies telles que le carbure de silicium pour la conception des interrupteurs MOSFET. Cette technologie présente des problèmes de fiabilité tels que la robustesse face au phénomène d’avalanche, face aux courts-circuits, ainsi que l’instabilité de la tension de seuil et la robustesse de l’oxyde de grille. Ce papier présente les principaux problèmes de fiabilité ainsi qu’une étude sur la robustesse de l’oxyde de grille et l’instabilité de la tension de seuil. Les résultats obtenus montrent que les problèmes liés à l’oxyde de grille se sont beaucoup minimisé, bien qu’il reste quelques problèmes sur la stabilité de la tension de seuil des qu’on sollicite la diode interne. Donc, on peut conclure que les MOSFET SiC sont relativement robustes pour des applications industrielles en ce qui concerne la fiabilité de l’oxyde de grille

Statistical Study of Nanocrystalline Alloy Cut Cores From Two Different Manufacturers

International audienceThe classic shape of a magnetic circuit made of nanocrystalline alloy is usually the toroidal one. In power electronics, this shape is not the best one in terms of size and congestion. For high power magnetic components, the UU or CC shape (the cores look like the letter U or C) is preferred. Recently, two manufacturers have commercialized new magnetic circuits made of nanocrystalline alloy in this last shape. But before using these new products in power electronics, we have to first know them well and to be sure that they will respond adequately to the peculiar needs of the application. In this paper, we compare several cut cores geometric dimensions and magnetic properties from two different manufacturers. Full amplitude characterizations are performed. The dispersions of the samples and the agreement to datasheets are presented

Statistical study of Nanocristalline alloy cut-cores from two different manufacturers

International audienceThe " classic " shape of a magnetic circuit made of nanocrys-talline alloy is usually the toroidal one. In power electronics, this shape is not the best one in terms of size and congestion. For high power magnetic components, the UU or CC shape is preferred. Recently two manufacturers have commercialized new magnetic circuits made of nanocrystalline alloy in this last shape. But before using these new products in power electronics, we have, first to know them well and to be sure that they will respond adequately to the peculiar needs of the application. In this paper, we compare several cut cores geometric dimensions and magnetic properties from two different manufacturers. Full amplitude characterisations are performed. The dispersions of the samples and the agreement to datasheets are presented

Threshold voltage instability in SiC MOSFETs as a consequence of current conduction in their body diode

International audienceAn antiparallel PiN diode is present in the structure of the SiC Power MOSFET. For simplicity, increased module current ratings, and cost reasons, it sometimes may be preferable to use this diode rather than to add an external Schottky diode to the MOSFET. However, SiC PiN diodes are sensitive to defects in the SiC crystal, and their performance can degrade rapidly. In this paper, we assess the effect of several stresses on the characteristics of a SiC MOSFET, focusing on the stresses which involve the body diode. We demonstrate that using the body diode does not degrade its performances. However, it may produce a noticeable shift in the threshold voltage of the MOSFET. While this behaviour is observed for MOSFETs from one manufacturer, it is not exhibited for others, which indicates that it may be a consequence of some particular design or manufacturing parameters