Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (RON_dyn) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (RDSON) characteristics under 60Co gamma radiation of two different commercial power GaN HEMT structures. Different bias conditions were applied to both structures during irradiation and some static measurements, such as threshold voltage and leakage currents, were performed. Additionally, dynamic resistance was measured to obtain practical information about device trapping under radiation during switching mode, and how trapping in the device is affected by gamma radiation. The experimental results showed a high dependence on the HEMT structure and the bias condition applied during irradiation. Specifically, a free current collapse structure showed great stability until 3.7 Mrad(Si), unlike the other structure tested, which showed high degradation of the parameters measured. The changes were demonstrated to be due to trapping effects generated or enhanced by gamma radiation. These new results obtained about RON_dyn will help elucidate trap behaviors in switching transistors

On the Entropy of Oscillator-Based True Random Number Generators under Ionizing Radiation

The effects of ionizing radiation on field-programmable gate arrays (FPGAs) have been investigated in depth during the last decades. The impact of these effects is typically evaluated on implementations which have a deterministic behavior. In this article, two well-known true-random number generators (TRNGs) based on sampling jittery signals have been exposed to a Co-60 radiation source as in the standard tests for space conditions. The effects of the accumulated dose on these TRNGs, an in particular, its repercussion over their randomness quality (e.g., entropy or linear complexity), have been evaluated by using two National Institute of Standards and Technology (NIST) statistical test suites. The obtained results clearly show how the degradation of the statistical properties of these TRNGs increases with the accumulated dose. It is also notable that the deterioration of the TRNG (non-deterministic component) appears before that the degradation of the deterministic elements in the FPGA, which compromises the integrated circuit lifetime.Ministerio de Economía y Competitividad (ESP-2015-68245-C4-1-P)Ministerio de Economía y Competitividad (ESP-2015-68245-C4-4-P)Ministerio de Economía y Empresa (TIN2016-79095-C2-2-R)CAM (S2013/ICE-3095

Total Ionizing Dose Effects on a Delay-Based Physical Unclonable Function Implemented in FPGAs

Physical Unclonable Functions (PUFs) are hardware security primitives that are increasingly being used for authentication and key generation in ICs and FPGAs. For space systems, they are a promising approach to meet the needs for secure communications at low cost. To this purpose, it is essential to determine if they are reliable in the space radiation environment. In this work we evaluate the Total Ionizing Dose effects on a delay-based PUF implemented in SRAM-FPGA, namely a Ring Oscillator PUF. Several major quality metrics have been used to analyze the evolution of the PUF response with the total ionizing dose. Experimental results demonstrate that total ionizing dose has a perceptible effect on the quality of the PUF response, but it could still be used for space applications by making some appropriate corrections.Ministerio de Economía y Competitividad ESP2015-68245-C4-1-P, ESP-2015-68245-C4-4-P

On the applications of IBA techniques to biological samples analysis: PIXE and RBS

The analyticaltechniques based on ion beamsorIBA techniquesgive quantitativeinformationonelemental concentrationin samples of awide variety of nature. In this work, weinformation on elemental concentrationin samples of awide variety of nature. In this work, weinformation on elemental concentrationin samples of awide variety of nature. In this work, weinformation on elemental concentrationin samples of awide variety of nature. In this work, wefocus on PIXE technique,analyzingthick target biologicalspecimens (TTPIXE),using 3MeVfocus on PIXE technique,analyzingthick target biologicalspecimens (TTPIXE),using 3MeVfocus on PIXE technique,analyzingthick target biologicalspecimens (TTPIXE),using 3MeVfocus on PIXE technique,analyzingthick target biologicalspecimens (TTPIXE),using 3MeVprotons producedby an electrostaticaccelerator.Anuclear microprobewas used performingprotons producedby an electrostaticaccelerator.Anuclear microprobewas used performingprotons producedby an electrostaticaccelerator.Anuclear microprobewas used performingprotons producedby an electrostaticaccelerator.Anuclear microprobewas used performingPIXEandRBSsimultaneously,inordertosolvetheuncertaintiesproducedintheabsolutePIXEPIXEandRBSsimultaneously,inordertosolvetheuncertaintiesproducedintheabsolutePIXEPIXEandRBSsimultaneously,inordertosolvetheuncertaintiesproducedintheabsolutePIXEPIXEandRBSsimultaneously,inordertosolvetheuncertaintiesproducedintheabsolutePIXEquantifying. Theadvantages of using both techniquesand anuclear microprobearediscussed.quantifying.Theadvantages of using both techniquesand anuclear microprobearediscussed.quantifying.Theadvantages of using both techniquesand anuclear microprobearediscussed.quantifying.Theadvantages of using both techniquesand anuclear microprobearediscussed.Quantitative resultsare shown to illustrate themultielemental resolutionof the PIXE technique;Quantitativeresults are shown to illustrate themultielemental resolutionof the PIXE technique;Quantitativeresults are shown to illustrate themultielemental resolutionof the PIXE technique;Quantitativeresults are shown to illustrate themultielemental resolutionof the PIXE technique;forthis,abloodstandardwasused.forthis,abloodstandardwasused.forthis,abloodstandardwasused.forthis,abloodstandardwasused

A view of the implanted SiC damage by Rutherford backscattering spectroscopy, spectroscopic ellipsometry, and transmission electron microscopy

4H-SiC single crystalline substrates were implanted at room temperature with 150 keV Al+ ions using fluences of 4 1014, 1 1015, and 2 1015 cm−2 with current density of 2.5 A cm−2. The samples were subsequently annealed at 1100 °C in N2 for 1 h in order to analyze their structural recovery. The disorder induced in both sublattices by the Al+ ions was studied by backscattering spectrometry in channeling geometry with a 3.5 MeV He2+ beam. The results were compared with the optical properties of the samples measured by spectroscopic ellipsometry. In a previous work, we concluded that during the postimplantation annealing of a highly damaged SiC crystalline material the short distance order can be recovered, while the long distance disorder remains. We also presented the possibility to have grains of different polytypes oriented faraway from the original direction. Now, this alternative is confirmed by the cross-sectional transmission and high resolution electron microscopy studies, carried out to obtain information about the crystal structure.Ministerio de Cienncias y Tecnología español-MAT2002-02843 (70% de fondos FEDER)Acuerdo de Colaboración Científica Húngaro-Españo-lE27 / 2001Fondo de Investigaciones Científicas de Hungría (OTKA)-T032029, T047011, T043704 y K6172

Radiation Testing of a Multiprocessor Macrosynchronized Lockstep Architecture With FreeRTOS

Nowadays, high-performance microprocessors are demanded in many fields, including those with high-reliability requirements. Commercial microprocessors present a good tradeoff between cost, size, and performance, albeit they must be adapted to satisfy the reliability requirements when they are used in harsh environments. This work presents a high-end multiprocessor hardened with macrosynchronized lockstep and additional protections. A commercial dual-core Advanced RISC Machine (ARM) cortex A9 has been used as a case study and a complete hardened system has been developed. Evaluation of the proposed hardened system has been accomplished with exhaustive fault injection campaigns and proton irradiation. The hardening approach has been accomplished for both baremetal applications and operating system (OS)-based. The hardened system has demonstrated high reliability in all performed experiments with error coverage up to 99.3% in the irradiation experiments. Experimental irradiation results demonstrate a cross-sectional reduction of two orders of magnitude.This work was supported in part by the Spanish Ministry of Science and Innovation under Project PID2019-106455GB-C21 and in part by the Community of Madrid under Project 49.520608.9.18Publicad

All chemical YBa2Cu3O7 superconducting multilayers: Critical role of CeO2 cap layer flatness

New advances toward microstructural improvement of epitaxial Ce0 2 films grown by chemical solution deposition and their use as buffer layers for YBa2Cu3O7 (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr4+) or trivalent (Gd3+) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction. In addition, we use a new methodology to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm-2 at 77 K. © 2009 Materials Research Society.We acknowledge the financial support from MEC (MAT2005-02047, and CONSOLIDER NANOSELECT), Generalitat de Catalunya (Catalan Pla de Recerca SGR-0029 and CeRMAE), EU (HIPERCHEM, NMP4-CT2005-516858). J. Gàzquez, M. Coll, and A. Pomar are grateful to Spanish Ministery of Educacion y Ciencia (MEC) for financial support through Formacion de Personal Investigador (FPI), Formacion de Profesorado Universitario (FPU), and “Ramón y Cajal” programs.Peer Reviewe

Hyperthermia iatrogenic with thermal blanket for patient under total pelvic exenteration

Exponemos un caso clínico con el objetivo de mostrar como puede presentarse un cuadro de hipertermia con consecuencias hemodinámicas graves, así como destacar que un diagnóstico (clínico y mediante sistemas de monitorización mínimamente invasivos) y tratamiento precoces son imprescindibles para conseguir una adecuada evolución del paciente. Es un caso de hipertermia iatrogénica en un hombre de 59 años sometido a exenteración pélvica total. Mostramos cómo la hipertermia puede presentarse con repercusión clínica importante y grave, en forma de Síndrome de Respuesta Inflamatoria Sistémica, que puede poner en peligro la vida del paciente, y como su diagnóstico y tratamiento precoz (mediante la monitorización con el sistema VIGILEO) puede ser clave para que la evolución del cuadro sea adecuada. La conclusión a la cual queremos llegar es que la hipertermia puede presentarse como un SRIS y que la monitorización hemodinámica y de la temperatura corporal puede ayudarnos en su diagnóstico y tratamiento.We report a case in order to show how you can present with symptoms of hyperthermia with severe hemodynamic consequences and noted that a diagnosis (clinically and by systems of minimally invasive monitoring) and early treatment are essential for adequate patient outcome. It’s a case of iatrogenic hyperthermia in a man of 59 years underwent total pelvic exenteration. We show how hyperthermia can present with significant and serious clinical consequences, as syndrome systemic inflammatory response, which may endanger the patient’s life, as early diagnosis and treatment (by monitoring the Vigileo system) can be key to the evolution of the condition is appropriate. The conclusion at which we arrive is that hyperthermia may occur as a SIRS and hemodynamic and body temperature monitoring may help in diagnosis and treatment

How the analysis of archival data could provide helpful information about TID degradation. Case study: Bipolar transistors

A critical step of radiation hardness assurance (RHA) for space systems is given by the parts selection in accordance with the observed (or estimated) radiation effects. Although radiation testing is the most decisive way of studying the radiation degradation of electronic components, the increasing use of commercial off-the-shelf (COTS) devices and the challenges posed by NewSpace are pushing the need of finding new approaches to assess the risk associated with radiation environments. This work tries to evaluate if valuable information might be extracted from archival data to carry out this assessment despite the well-known and dramatic lot-to-lot, or even part-to-part, variability for some technologies and the impact of the different test conditions, such as the bias conditions and the dose rate in enhanced low dose rate sensitivity (ELDRS). These factors are briefly analyzed for some examples. A new radiation database is briefly introduced, and some statistical approaches are cited, apart from the analysis herein followed. To finish, a first analysis on three families of bipolar transistors is presented together with the independent results from three external reports, with a good agreement between the experimental results and the expected ones.10.13039/501100002878-Junta de Andalucia and Fondo Europeo de Desarrollo Regional (FEDER) Funds through the Singular Project Predicción del Comportamiento Eléctrico de Dispositivos Electrónicos bajo Radiación (PRECEDER) (Grant Number: CEI-5-RNM138). 10.13039/501100004837-Spanish Ministry of Science and Innovation under Project (Grant Number: PID2019-108377RB-C32)Peer reviewe

Accelerator-based research activities at "Centro Nacional de Aceleradores", Seville (Spain)

5 páginas.-- PACS nrs.: 29.17.+w; 29.20.−c; 82.80.−d; 07.30.Kf.In February 1998, almost 10 years ago, the set-up of the first IBA (ion beam analysis) facility in Spain took place with the arrival of a 3 MV tandem accelerator [J. García-López, F.J. Ager, M. Barbadillo-Rank, F.J. Madrigal, M.A. Ontalba, M.A. Respaldiza, M.D. Ynsa, Nucl. Instr. and Meth. B 161–163 (2000) 1137]. Since then, an intensive research program using IBA techniques has been carried out. Subsequently, a cyclotron for 18 MeV protons has been also installed at the “Centro Nacional de Aceleradores” (CNA), devoted mainly to isotope production for PET (positron emission tomography) techniques, but possibly applied to material analysis and damage studies on a dedicated beam line. Moreover, a 1 MV tandem has been recently installed for AMS (accelerator mass spectrometry) 14C dating and environmental research with other isotopes.In the present paper we describe the new facilities and the developments of the 3 MV tandem beam lines occurred during the past years, as well as some examples of the most recent research activities in our Center in the fields of Material Science, Archaeometry, Biomedicine and Environment.Thanks are due to the three host Institutions, Universidad de Sevilla, Junta de Andalucía and CSIC, for the continuous support given to our Centre.Peer reviewe