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Irradiation of lithium fluoride with protons causes the formation of electronic defects, known as colour centres, in the crystal lattice. Two stable defects among them, the F2 and F3+ aggregate ones, under blue light simultaneous excitation show broad photoluminescence in the red and green visible spectral ranges, respectively, their peculiar characteristics being well known for applications in optically-pumped tuneable lasers, broad-band miniaturized light-emitting photonic devices and passive radiation imaging detectors. Recently, exploitation of their radiophotoluminescence has been successfully proposed for proton-beam advanced diagnostics and dosimetry, even at low dose values typical of radiotherapy. In the present study, lithium fluoride crystals were irradiated with 2.3 MeV protons in the dose range from ∼104 to ∼107 Gy and their dynamic range, that is the capability of detecting the widest possible range of radiophotoluminescence intensity emitted by the colour centres, was found to be 114 dB at the F2 peak emission wavelength of 675 nm under continuous-wave laser excitation at 445 nm. Moreover, after including in the analysis a set of lithium fluoride crystals irradiated with 26.1 MeV protons in the dose range from 0.5 to 48 Gy at a much lower dose-rate, it was found that the radiophotoluminescence intensity of the F2 colour centres shows a linear dependence with dose from 0.5 to ∼2 × 105 Gy.

In a medical accelerator, real-time monitoring systems of the beam and dose delivered to the patient are mandatory. In this work, we present a compact current profile detector that has been designed and tested in the framework of the TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTerapy) project. This project foresees the realization of a proton linear accelerator, currently under construction at ENEA Frascati, for proton therapy applications. The linac produces a pulsed proton beam with 3 µs duration at 50 Hz repetition rate with a pulse current between 0.5 and 50 μA. A large dynamic range and spatial constraints make the use of usual noninterceptive beam diagnostics unfeasible. Therefore, the use of a beam current monitor based on a passive RF cavity working in the TM010 mode has been proposed. This paper reports the electromagnetic design of the device guided by a simplified analytical model. A prototype of such a device has been realized, characterized, and tested on the linac with a 35 MeV beam varying the beam current. The test results in air and in vacuum, together with the signal detection systems used, are presented.

Solid-state radiation detectors based on the visible photoluminescence of radiation-induced F2 and F3+ color centers in lithium fluoride crystals have been used for advanced diagnostics of 18 and 27 MeV proton beams, produced by the TOP-IMPLART linear accelerator, which is under development for protontherapy applications at ENEA C.R. Frascati, Italy. Visible fluorescence microscopy was successfully used to read the latent proton beam images stored in the lithium fluoride crystals, thanks to high emission efficiency of the F2 and F3+ color centers obtained by simultaneous optical excitation in the blue spectral range. High intrinsic spatial resolution and wide dynamic range of these novel LiF detectors allow obtaining two-dimensional images of both the beam transverse intensity distribution and of the Bragg curve. By using a simple defect formation model that takes into account the energy released in the material and the saturation of defect concentration, not only the two-dimensional dose map was obtained from the beam transverse intensity distribution image, but also the full Bragg curve was reconstructed, allowing the thorough characterization of proton beams produced by the accelerator.

This paper presents the experimental results on the Terapia Oncologica con Protoni-Intensity Modulated Proton Linear Accelerator (TOP-IMPLART) beam that is currently accelerated up to 35 MeV, with a final target of 150 MeV. The TOP-IMPLART project, funded by the Innovation Department of Regione Lazio (Italy), is led by Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) in collaboration with the Italian Institute of Health and the Oncological Hospital Regina Elena-IFO. The accelerator, under construction and test at ENEA-Frascati laboratories, employs a commercial 425 MHz, 7 MeV injector followed by a sequence of 3 GHz accelerating modules consisting of side coupled drift tube linac (SCDTL) structures up to 71 MeV and coupled cavity linac structures for higher energies. The section from 7 to 35 MeV, consisting on four SCDTL modules, is powered by a single 10 MW klystron and has been successfully commissioned. This result demonstrates the feasibility of a ``fully linear'' proton therapy accelerator operating at a high frequency and paves the way to a new class of machines in the field of cancer treatment.

MOS-Modelle und Parameterextraktion Arbeitskreis MOS-AK is a European, independent compact modelling forum created by a group of engineers, researchers and compact modelling enthusiasts to promote advanced compact modelling techniques and model standardization using high-level behavioural modelling languages such as VHDL-AMS and Verilog-A. This invited paper summarizes recent MOS-AK open-source compact model standardization activities and presents advanced topics in metal-oxide-semiconductor field-effect transistor modelling, focusing in particular on analogue/radio frequency applications. The paper discusses links between compact models and design methodologies, finally introducing elements of compact model standardization. The open-source computer-aided design tools Qucs, QucsStudio and ngspice all support Verilog-A as a hardware description language for compact model standardization. Latter sections of this paper describe a Verilog-A implementation of the EKV3 MOS transistor model. Additionally, the simulated radio frequency model performance is evaluated and compared with experimental results for 90nm CMOS technology. Copyright © 2014 John Wiley & Sons, Ltd.

Terahertz image sensors have large potential in time-domain spectroscopy, radio astronomy, security control, communications, and biomedical imaging. We present a new structure for THz imaging, obtained by the combination of a CMOS photodetector, and a rectennas composed by a tapered μ-helix monopole and a rectifying device. The antenna consists in a truncated conical helix extruded from a planar spiral and in a nanometric metallic whisker connected to one of its edges. We introduce the new structure together with an accurate study of the effect of electric field enhancement and of parasitic elements which affect the overall sensitivity of the device.

Static leakage currents represent a major issue in nano-scale CMOS. In digital VLSI circuits, the most relevant contributions to the overall leakage current are subthreshold conduction, gate current and band-to-band-tunneling (BTBT) current, which flows from drain/source to bulk through the reverse biased diffusion junctions. While the latter has been recognized as an important effect in digital nano-CMOS, yet no compact model of it has ever been included in the industry-standard device model BSIM4. In this work, we show that the lack of a BTBT current model leads to discrepancies between SPICE and device-level simulations and that adding a BTBT current source into BSIM4 DC model can correct this. The new current source follows a widely accepted physical model of the BTBT phenomenon with a rectangular junction approximation. Test case results show a good agreement between the new circuit-level simulations and the device-level extracted currents.

Copper (II) sulfate was used as a source of copper to achieve uniform distribution of Cu particles deposited on porous silicon. Layers of the porous silicon were formed by electrochemical anodization of Si wafers in a mixture of HF, C3H7OH and deionized water. The well-known chemical displacement technique was modified to grow the copper particles of specific sizes. SEM and XRD analysis revealed that the outer surface of the porous silicon was covered with copper particles of the crystal orientation inherited from the planes of porous silicon skeleton. The copper crystals were found to have the cubic face centering elementary cell. In addition, the traces of Cu2O cubic primitive crystalline phases were identified. The dimensions of Cu particles were determined by the Feret's analysis of the SEM images. The sizes of the particles varied widely from a few to hundreds of nanometers. A phenomenological model of copper deposition was proposed.

This article presents the study of the electrochemical deposition of zinc oxide from the non-aqueous solution based on dimethyl sulfoxide and zinc chloride into the porous silicon matrix. The features of the deposition process depending on the thickness of the porous silicon layer are presented. It is shown that after deposition process the porous silicon matrix is filled with zinc oxide nanocrystals with a diameter of 10–50 nm. The electrochemically deposited zinc oxide layers on top of porous silicon are shown to have a crystalline structure. It is also shown that zinc oxide crystals formed by hydrothermal method on the surface of electrochemically deposited zinc oxide film demonstrate ultra-violet luminescence. The effect of the porous silicon layer thickness on the morphology of the zinc oxide is shown. The structures obtained demonstrated two luminescence bands peaking at the 375 and 600 nm wavelengths. Possible applications of ZnO nanostructures, porous and continuous polycrystalline ZnO films such as gas sensors, light-emitting diodes, photovoltaic devices, and nanopiezo energy generators are considered. Aspects of integration with conventional silicon technology are also discussed.

In this work the design and characteristics of an extended hemispherical dielectric lens applied to a non-planar antenna for the detection of THz radiation is presented. Antenna and lens behavior is numerically investigated in a large frequency range around the central frequency of 1 THz. Common printable materials widely characterized at THz range are used for the lens realization. Numerical results of the full-wave electromagnetic analysis of some proposed structures are reported and discussed.

A new selective processing technique based on a confined dynamic liquid drop\meniscus is presented. This approach is represented by the localized wet treatment of silicon wafers using dynamic liquid drop that while is in contact with the wafer forms a dynamic liquid meniscus. The main scientific innovation and relevance introduced by this work have been applied to industrial solar cell production and on silicon wafer metal bumps formation for the IC interconnection (i.e. copper pillars). Such new technique allows to touch in specific defined positions the silicon wafer in order to perform any kind of wet processing (e.g. etching, cleaning and/or plating) without the need of any protective resist. To investigate on pendant dynamic liquid drops and dynamic liquid meniscus use of computational fluid dynamic technique (i.e. numerical techniques to accurately predict fluid flows) was followed and is presented. An experimental setup has been built to validate the calculations. Numerical results showed a good agreement with experimental ones. Prototypes heads, using stereo-lithography systems, were developed and localized selective plating without the need of lithography step was performed on silicon.

In this work we present a new design for a three-dimensional vibration energy harvester, which is made by Micro-Electro-Mechanical Systems (MEMS) technology, and which can convert electric energy through transverse mode piezoelectric effect. The presented power generator is based on a long, thick-film, piezoelectric beam configured as a conical helix structure and located between two metal electrodes. The design of the combined antenna/energy harvester (comvester, from communication and energy harvester) device addresses both electromagnetic and mechanical issues as it radiates electromagnetic energy and converts mechanical energy into electric energy. Both functions are translated directly into dimensional constraints of the structure. In this work, we concentrate on millimeter waves communications in the 60 GHz frequency band because of their availability for low-power CMOS radio circuits. In order to realize comvester on a silicon wafer we used Controlled Release Metal Layer (CRML) technology, which is a transfer layer technology that uses porous silicon as sacrificial material. The advantage of CRML technology is high repeatability and resolution and its compatibility with back-end of line processes of the integrated circuit industry. New type of piezoelectric material consisted of the array of separated vertical polyvinylidene fluoride (PVDF) microrods is suggested. Such periodic microrods structure became possible to realize using the template of the structured macroporous silicon.

In this work the design of a broadband, high gain conical helical antenna is presented. The antenna is realized using a MEMS process that guarantees the high repeatability and throughput necessary for industrial applications. The designed antenna works in the 55GHz to 85GHz frequency range and has a gain greater than 8 dBi. This antenna presents potential applications in the emerging 60GHz communication band (assigned to WPAN) and in 76GHz RADAR applications for the automotive industry. The design procedure, mechanical and electromagnetic simulations are presented.

In this work it is described an high-density contacting technology that can replace wire bonding in power electronic applications, to overcome known limitation of bond wires liftoff occurring after several power cycles due to the difference in the coefficient of thermal expansion of silicon and aluminum. In the presented technology, MEMS (micro-electro-mechanics systems) micro-fabrication processes are used to realize contact structures that, pressed against the silicon dice, provide a reliable compliant contact. One advantage of this technology is that the contacts can be hosted on a printed circuit board that integrates the control circuitry for the power devices. This will reduce the footprint of power systems, like Integrated High Power Modules (IHPM). Reduced footprints are beneficial in applications where space is a concern, like the automotive industry. The description of the technological steps for building the contacting assembly is reported together with process conditions and electrical performances of two test structures.

In this work a new class of integrated 3D antennas is presented: the u-helix antenna class. U-helix is a truncated conical helix built using a novel MEMS (micro electro mechanical systems) technology directly realized on a silicon substrate, extruded from a planar spiral. The antenna is characterized by high gain (>6 dBi) and wide fractional bandwidth (0.4) in the 100 GHz to 1 THz frequency range. Fabrication processes of the antenna and simulated performances are reported, and its possible use in a THz rectifying device is presented.

The electrochemotherapy is an effective treatment that requires the application of an intense electric field to the tumoral tissue to open the cellular membrane and deliver drugs. This work will present the results of the ongoing research project, showing a new technology and design geometry that allows to realize flexible electrodes able to wrap biological tissues bringing the necessary electric field intensity for the electroporation of cells to reach a unique penetration depth to the centimeter range. The flexible electrode is realized by conversion of porous silicon into nano-porous metals (copper and/or gold) filled by a biocompatible thermoplastic polymer.

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