8,109 research outputs found

    Radiation damages in CMOS image sensors: testing and hardening challenges brought by deep sub-micrometer CIS processes

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    This paper presents a summary of the main results we observed after several years of study on irradiated custom imagers manufactured using 0,18 µm CMOS processes dedicated to imaging. These results are compared to irradiated commercial sensor test results provided by the Jet Propulsion Laboratory to enlighten the differences between standard and pinned photodiode behaviors. Several types of energetic particles have been used (gamma rays, X-rays, protons and neutrons) to irradiate the studied devices. Both total ionizing dose (TID) and displacement damage effects are reported. The most sensitive parameter is still the dark current but some quantum eficiency and MOSFET characteristics changes were also observed at higher dose than those of interest for space applications. In all these degradations, the trench isolations play an important role. The consequences on radiation testing for space applications and radiation-hardening-by-design techniques are also discussed

    Three-dimensional charge transport mapping by two-photon absorption edge transient-current technique in synthetic single-crystalline diamond

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    We demonstrate the application of two-photon absorption transient current technique to wide bandgap semiconductors. We utilize it to probe charge transport properties of single-crystal Chemical Vapor Deposition (scCVD) diamond. The charge carriers, inside the scCVD diamond sample, are excited by a femtosecond laser through simultaneous absorption of two photons. Due to the nature of two-photon absorption, the generation of charge carriers is confined in space (3-D) around the focal point of the laser. Such localized charge injection allows to probe the charge transport properties of the semiconductor bulk with a fine-grained 3-D resolution. Exploiting spatial confinement of the generated charge, the electrical field of the diamond bulk was mapped at different depths and compared to an X-ray diffraction topograph of the sample. Measurements utilizing this method provide a unique way of exploring spatial variations of charge transport properties in transparent wide-bandgap semiconductors.Comment: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.509085

    Patterned Nanomagnetic Films

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    Nano-fabrication technologies for realising patterned structures from thin films are reviewed. A classification is made to divide the patterning technologies in two groups namely with and without the use of masks. The more traditional methods as well as a few new methods are discussed al in relation with the application. As mask less methods we discussed direct patterning with ions including FIB, nanopaterning with electron beams, interferometric laser annealing and ion beam induced chemical vapour deposition. The methods using masks are ion irradiation and projection, interference lithography, the use of pre-etched substrates and templates from diblock copolymers and imprint technologies. First a few remarks are given about the magnetic properties of patterned films but the main part of this paper is focussed on the various patterning technologies. Finally two important applications are summarized such as media for ultra high-density recording and magnetic logic devices. Nanometer scale magnetic entities (nanoelements, nanodots, nanomagnets) form a fast growing new area of solid-state physics including the new fields of applications

    Precision Crystal Calorimetry in High Energy Physics

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    Crystal Calorimetry is widely used in high energy physics because of its precision. Recent development in crystal technology identified two key issues to reach and maintain crystal precision: light response uniformity and calibration in situ. Crystal radiation damage is understood. While the damage in alkali halides is found to be caused by the oxygen/hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides.Comment: 8 pages with 13 eps Figures, RevTe

    Organic Single-Crystal Field-Effect Transistors

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    We present an overview of recent studies of the charge transport in the field effect transistors on the surface of single crystals of organic low-molecular-weight materials. We first discuss in detail the technological progress that has made these investigations possible. Particular attention is devoted to the growth and characterization of single crystals of organic materials and to different techniques that have been developed for device fabrication. We then concentrate on the measurements of the electrical characteristics. In most cases, these characteristics are highly reproducible and demonstrate the quality of the single crystal transistors. Particularly noticeable are the small sub-threshold slope, the non-monotonic temperature dependence of the mobility, and its weak dependence on the gate voltage. In the best rubrene transistors, room-temperature values of μ\mu as high as 15 cm2^2/Vs have been observed. This represents an order-of-magnitude increase with respect to the highest mobility previously reported for organic thin film transistors. In addition, the highest-quality single-crystal devices exhibit a significant anisotropy of the conduction properties with respect to the crystallographic direction. These observations indicate that the field effect transistors fabricated on single crystals are suitable for the study of the \textit{intrinsic} electronic properties of organic molecular semiconductors. We conclude by indicating some directions in which near-future work should focus to progress further in this rapidly evolving area of research.Comment: Review article, to appear in special issue of Phys. Stat. Sol. on organic semiconductor

    Thermal imaging in the 3-5 micron range for precise localization of defects: Application on frescoes at the Sforza Castle

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    Infrared methods are of great importance in nondestructive testing of artworks, allowing a remote and wide-field imaging of interesting hidden features. Here we discuss a workflow based on thermal imaging in the mid infrared 3-5 micron range for the evaluation of subsurface defects in frescoes. Particular attention is payed to obtaining a high resolution (submillimetric) localization of the defects. The transfer of diagnostics techniques into real world applications, is discussed through the proof of concept of the proposed workflow on frescoes at the Sforza Castle (Milan, Italy)
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