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The design of solid-state materials whose properties and functions can be manipulated in a controlled manner by the application of electron beam irradiation is important in modern materials chemistry and physics. In this paper, we present a progress in the development of scalable electron beam irradiation platform to obtain innovative materials for technological and industrial applications, since one of the problems to be solved in this research area is the scalability of these new nanomaterials induced by electron beam irradiation (EBI). In particular, we focus on carbon structures due to its excellent and exciting properties applied in the technological area in the last years, where we show for the first time a new strategy for carbon allotropic transformation through the portable EBI. This new platform is particularly effective, fast, versatile, clean and easy-to-use, facilitating the preparation of many types of nanomaterials that cannot be obtained by conventional chemical and physical methods. The EBI on flat graphite pellets resulted in a covering of it surface with rod-like particles composed of different allotropic forms of carbon. Furthermore, the developed system allowed the implantation of the Fe as a catalytic material through steel sputtering of the high voltage acceleration anode during the EBI process. It was observed by HRTEM analyses that the rod-like particles are preferentially composed of highly oriented graphite in its bottom, polycrystalline graphite in its middle and magnetite nanoparticles in its top.

This study demonstrates that the electron beam irradiation of materials, typically used in characterization measurements, could be employed for advanced fabrication, modification, and functionalization of composites. We developed irradiation equipment using an electron beam irradiation source to be applied in materials modification. Using this equipment, the formation of a thick Ag film on the Ag3PO4 semiconductor is carried out by electron beam irradiation for the first time. This is confirmed by various experimental techniques (X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy) and ab initio molecular dynamics simulations. Our calculations demonstrate that, at the earlier stages, metallic Ag growth is initiated preferentially at the (110) surface, with the reduction of surface Ag cations forming metallic Ag clusters. As the (100) and (111) surfaces have smaller numbers of exposed Ag cations, the reductions on these surfaces are slower and are accompanied by the formation of O2 molecules.

This work presents a capacitive modulator design and modeling of a new waveguide architecture using silicon and poly-si technologies. We use a methodology involving the entire lumped-type modulator design process, from the optical design to the small-signal RF analysis. By means of geometric and physical parameters adjustments, the trade-offs among several figures of merit are analyzed in this paper. Due to the waveguide configuration, it is shown that the modulator can improve the trade-off between $V_{\pi }$ and bandwidth compared to the state-of-the-art for this kind of device. For instance, the best combinations are $V_{\pi }\simeq$ 1 V @ 20.4 GHz and $V_{\pi }$ = 5.7 V @ $\sim$ 31 GHz, with equivalent optical losses of 3 dB and 1.1 dB, respectively.

A Silicon (Si) modulator and a design methodology using a system-oriented numerical approach are proposed. The main contributions of this work are to provide a Silicon modulator as an alternative solution for intra-data center interconnect (DCI) applications and a single figure-of-merit (FOM) for the modulator design, which takes as input the main device parameters (modulation efficiency ( V π × L ), optical loss, and electro-optical bandwidth ( f 3 d B )) and provides a global optical system optimization. By using a numerical approach, the modulator physical parameters are analyzed according to system performance metrics such as the required receiver sensitivity to reach a target bit error rate (BER), and the required transmitter launch power. A capacitive Silicon device and a 4-level pulse amplitude modulation (PAM-4) system simulator is presented. The results show an efficient modulator ( V π = 3.5 V ) with high bandwidth ( f 3 d B > 38 GHz ), which is promising for data centers solutions, where power consumption is critical and high-speed is required.

This paper presents a system for characterization of thermoelectric generators (TEGs) for energy harvesting. This system can monitor and characterize up to three TEGs simultaneously and it is comprised by two main electronic circuits: The first one is composed by twelve input channels being three for reading voltage, three for reading current by making use of instrumentation amplifiers (reference ACS712) and six thermocouples for signal reading (

Several industrial applications require liquid characterization during manufacturing to ensure quality in their products. Examples of such products are those related to food and oil industries in which one of the concerns regards the different concentration of liquids in a mixture. In this context, it is presented a system based on ferroelectret transducers and low-cost technology to perform liquid analysis through acoustic measurements. The developed system is composed of three parts: a piezoelectric actuator, a medium chamber and a ferroelectret transducer (acoustic sensor). The system was assembled with a ferroelectret (with open tubular channels) housed on a cylindrical aluminum case (48 mm × 63 mm) in which a 24 dB preamplifier was mounted. The specifically designed chamber was manufactured in ABS plastic using a 3D printer and the piezoelectric actuator consisted in commercial piezoelectric ceramic which is connect to signal generator configured to generate a sinusoidal sweep between 0 Hz up to 50 kHz during 1 s. In order to characterize the device setup and validate the suitableness of the measuring system, three distinct mediums were analyzed (air, water and oil). Through the experimental tests it was identified, on time domain, distinct signatures for each medium, which were later used in a blind classification with a developed algorithm.

This paper proposes a Flexible Infrastructure for Dynamic Power Control (FIDPC) of Electric Vehicle (EV) Battery Chargers. This infrastructure dynamically adjusts the EV battery charger current, according to the power demand of the home wherein the vehicle is plugged. An infrastructure was implemented to validate this proposal. Such infrastructure is composed by an EV battery charger and a communication system based on a Radio Frequency interface. The battery charger has nominal power of 3.6 kVA and operates with sinusoidal current and unitary total power factor, while the RF interface provides continuous data flow to the battery charger with information about the home total current consumption (rms value). Experimental tests were performed under realistic conditions to validate the concept behind the proposed FIDPC. These tests served to assess the behavior of the EV battery charger with dynamic power control on a single-phase, 230 V, 16 A, 50 Hz residential electrical installation. The experimental results confirm the quick time response of the FIDPC even when working under heavy home load variations., This work was supported by the Fundacao para a Ciencia e Tecnologia (FCT) through Project PEst-UID/CEC/00319/2013. The work of V. Monteiro was supported by the FCT agency through a doctoral scholarship under Grant SFRH/BD/80155/2011. The review of this paper was coordinated by Dr. D. Cao.

Every year, different areas of knowledge are becoming more interested in 3D-printing technology. Recently, this technology was also proved to be feasible for creating sensitive materials such as piezoelectrets. This Letter extends the concept of a 3D printed piezoelectret to produce a pressure sensitive film that can be employed as an ultrasonic transducer for underwater applications, such as hydrophones. In order to achieve this, a two-layer polypropylene film was printed using a filament-based 3D printer. Afterwards, adhesive electrodes were attached on both sides of the film and electrical charging was applied. Later, the 3D printed film was mounted in a metal housing specially designed to keep the film in direct contact with the water and to isolate the electronic amplification. The validation was performed using a piezoelectric ceramic made of lead zirconate titanate (PZT), immersed in a water tank, to produce ultrasonic sweeps to be sensed by the 3D printed transducer. These tests revealed sensor sensitivities up to 600 mV and promote a precise detection of the acoustic resonance frequency of the PZT at 43.7 kHz.

This paper presents an optical sensor for angular measurements to perform precise tracking of the sun's incident angle in a photovoltaic system. This microdevice was designed using a 0.18μm CMOS technology from TSMC. The microdevice is composed by a matrix of photodiodes and their respective readout electronics. A set of microstructures were used to resolve the angles of rotation by measuring the angle of incident light in the microdevice. These microstructures were fabricated on top of the photodiodes using the same CMOS process. Simulations and experimental setup showed the possibility of taking measurements from the angles between −60 to 60 degrees.

This paper presents an up/down converter double-balanced Gilbert cell mixer for frequencies of 433, 870 and 928 MHz in the ISM band (industrial, scientific and medical). This mixer was designed with the on-semiconductor (former AMIS) 0.7μm CMOS technology. The Gilbert cell topology was selected due to its good figure of merit (FOM), which takes into account parameters such as the conversion gain (CG), isolation between the input ports, linearity and the noise figure. This mixer provides frequency translation by means of a true multiplication on four quadrants. The simulations showed a total power consumption of 3mW from a power supply of 5V, a CG of 10.5dB, an input referred third-order input intercept point (IIP3) of 29.72dBm and an input referred 1-dB compression point (IP1dB) of 13.15dBm. This paper also presents a comparison for the three bands in order to confirm the scalability and suitability of the mixer implemented. The target application of this mixer is to provide communication to/from intra-corporal communication devices.

This paper presents few developments on CMOS microelectronics for the implementation of photonic modules on endoscopic capsules (ECs). The first microelectronic system was developed with the goal to allow photodynamic therapy (PDT) on ECs. This first system was designed in the 2-metals/1-poly 0.7μm CMOS process from the on-semiconductor. The second development is an optical sensor designed for spectroscopy analysis on ECs from diffuse reflectance light originated in the gastrointestinal tissue. This second system was designed in the mixed-signal/RF 0.18μm CMOS general process from the Taiwan Semiconductor (TSMC).

This paper presents optical filters for narrow-band imaging on medical devices. Two optical filters were designed to provide an extremely narrow passband around the 415 nm (blue) and 540 nm (green) wavelengths using the Fabry-Perot phenomenon. Each filter is composed by successive thin-film layers of dielectric materials of titanium dioxide (TiO2) and silicon dioxide (SiO2). The TiO2 and SiO2 that compose the thin-films were fully characterized by ellipsometry applied within the 250–1700 nm wavelength range. The optical performance of the blue NBI optical filter (415 nm) was also measured. These filters were developed to integrate with light emitting diodes (LED) to provide the desired narrow-band imaging (NBI) bands on medical devices.

This paper presents a flexible thin-film (FTF) composed by a photovoltaic (PV) cell, a flexible solid-state rechargeable battery and power management electronics. A flexible printed circuit board (fPCB) was used for providing physical support to the electronics and to the battery, whereas a PDMS (polydimethylsiloxane) layer was used for providing mechanical adhesion between the PV cell and the fPCB. The high elasticity of the PDMS makes this material an excellent candidate for adapting two materials with different thermal expansions (fPCB and PV). The physical measurements showed a prototype with a thickness in the range 1.52 ± 0.10 mm, 10 g of weight and 37 × 114 mm of size. The electrical measurements showed ability to provide an output voltage of 3.8 V in a continuously form under these conditions: the PV providing DC power for solar irradiations higher than 6 W m−2, and the battery providing DC power for solar irradiations above bellow 6 W m−2 (value that has emerged during the twilight between sunset and dusk).

This paper analyses the influence of the coating process in the optical efficiency of replicated Moire´ Diffraction Gratings (MDGs), which are applied on real field applications for measuring both the surface displacements and strains. The Moire´ diffraction technique is an experimental full-field, non-contact and high resolution optical method, which can reveal to be very useful in extreme harsh environments. The optical efficiency of the replicated MDGs plays an important role in the quality of the experimental measurements. Two processes were used to obtain the metallic coatings: sputtering and aluminum vaporization. A good coatings quality with high optical efficiency was achieved for both processes (e.g., 17%–28%). However, for the replicated gratings a slight decrease in the optical efficiency was found (e.g., 14%–21%). The MDGs were successfully used for the experimental measurements of displacement and strains in a single lap joint. The measurements also showed that high quality of measurements allowed the identification of unbounded regions., This work was fully supported by the Portuguese Foundation for the Science and Technology (FCT) under the financial Grant FCOMP-01-0124-FEDER-010236, through Project Ref. FCT/PTDC/EME-PME/102095/2008.

Three-dimensional (3D) printing is a feasible solution for fast prototyping with precision in micrometer range. On the other hand, piezoelectrets are polymeric films with internal cavities, which has been electrically charged, resulting in a material with piezoelectric behavior. In the present paper, both, technology and concept were combined to produce structures with well-defined cavities and electromechanical properties. 3D printing can be performed in large range of materials, however for piezoelectret production the polymer must be electrically stable as in electrets. For this study, acrylonitrile butadiene styrene (ABS) was chosen as the base structural material and different voided structures were prepared. Results from pressure dependence and temporal stability are here presented.

This paper presents a photonic system based on Fiber Bragg Gratings (FBGs) for application to wearable garments. The objective is spanning the FBGs over the whole area of the garments for acting as sensing elements. The FBGs are embedded on a polychloroethanediyl (polyvinyl chloride, commonly abbreviated as PVC) carrier in order to increase their sensitivity to strains and for improving the simultaneous acquisition of respiratory and cardiac frequencies with only one FBG sensor. The global structure comprising FBGs and carrier allow high strain cycles and at the same time present linear behavior with the temperature, 17 pm º C -1. The measurements show a stable structure for temperatures up to 100 º C. This brings excellent perspectives for measuring the temperature with high accuracy and range. A set of tests were done by subjecting the FBG/carrier structure (with FBG stretched and no curves) to strains up to 1.2 mm, and it was also observed a linear behaviour: e.g., displacements of 0.8 pm εμ-¹. Behind its sensing enhancement operation, the carrier makes easy to mount the sensing structures., (/0025/2008)

In this paper is presented a fabrication process for obtaining refractive microlenses arrays with high reproducibility and low cost. This process was specifically optimized for the AZ4562 photoresist. Functional prototypes of microlenses arrays with dimensions in the range of 30 m, 4.9 mm and 5 m for width, length and thickness, respectively, were fabricated and tested. The pre-thermal reflow spacing between adjacent isosceles trapezoids is 1.35-5.43 m, from bottom to top, respectively. This separation allows the photoresist to reflow and join the adjacent microlens creating a consistent and homogeneous array., This work and Rui Pedro Rocha are fully supported by the Portuguese Foundation for Science and Technology under the project FCT/PTDC/EEA-ELC/109936/2009 and the financial grant SFRH/BD/33733/2009, respectively. The authors would also like to acknowledge Dr.-Ing Christian Koch from MicroChemicals GmbH for the technical support.

This paper presents a stereoscopic image sensor in CMOS technology. The proposed sensor allows the acquisition of stereoscopic images with a resolution of 1024×1024 pixels per channel and a targeted signal-to-noise ratio and dynamic-range of 60 dB. An array of microlenses (fabricated with post-processing techniques) separates the left and right optical channels to form the stereoscopic image. An array of optical filters tuned to the primary colors allows a multicolor usage. The fill factor is increased by applying the 1.5 transistor (1.5 T) concept and photodiodes with octagonal shapes. The reflow method applied to the AZ9260 thick photoresist allows the fabrication of microlenses with high reproducibility

This paper presents radio-frequency (RF) microsystems (MSTs) composed by low-power devices for use in wireless sensors networks (WSNs). The RF CMOS transceiver is the main electronic system and its power consumption is a critical issue. Two RF CMOS transceivers with low-power and low-voltage supply were fabricated to operate in the 2.4 and 5.7GHz ISM bands. The measurements made in the RF CMOS transceiver at 2.4GHz, which showed a sensitivity of -60dBm with a power consumption of 6.3mW from 1.8V supply. The measurements also showed that the transmitter delivers an output power of 0dBm with a power consumption of 11.2mW. The RF CMOS transceiver at 5.7GHz has a total power consumption of 23mW. The target application of these RF CMOS transceivers is for MSTs integration and for use as low-power nodes in WSNs to work during large periods of time without human operation, management and maintenance. These RF CMOS transceivers are also suitable for integration in thermoelectric energy scavenging MSTs.

Thin-film solid-state rechargeable batteries on silicon are ideal power sources for microsystems applications, where a high level of integration is required. This paper presents a lithium solid-state thin-film battery for integration in stand-alone microsystems. The thin-films were deposited by direct current (DC) and radio-frequency (RF) reactive sputtering techniques. The materials of the battery includes SnO2, Li3PO4N and LiCoO2 as anode, electrolyte and cathode, respectively. The SnO2 gives the battery a maximum storage capacity of 781 mAhg−1, the LiCoO2 can maintain a capacity of 140 mAhg−1. The two materials used as anode and cathode with the Li3PO4N as electrolyte can obtain an output voltage in the range 3-4.2 V.

This paper presents an acquisition system for measuring and characterization of thermoelectric generators (TEGs) for energy harvesting purposes on wireless sensors networks (WSNs). This system can monitor and characterize up to three TEGs simultaneously and is comprised of two main electronic circuits: the first one is composed of 12 input channels being three for reading voltage, three for reading current by making use of instrumentation amplifiers (ACS712), and six thermocouples for signal reading (

This paper presents a Low-Cost Flexible-Platform (LCFP) for measuring and characterizing photodetectors. This LCFP can characterize simultaneously up to 16 photodetectors and is composed by two main electronic circuit boards: a Transimpedance Amplifier Board (TIAB) and a Development Board (DevB). The TIAB was designed and optimized to reduce the noise increase, in order to convert photocurrents into voltages and at the same time, allowing the gain selection between one of the three values: 1 × 105 (low-gain, LG), 1 × 106 (medium-gain, MG) and 1 × 107 (high-gain, HG). The DevB is composed by 16 analog inputs, 54 digital inputs/outputs and an internal Analog to Digital Converter (ADC). It is possible to digitally change the Upper End Voltage (UEV) of the ADC's range to voltages below +5 V. The DevB can convert into the digital domain each one of the 16 analog signals from the TIAB with a resolution of 48.9 nA, 4.9 nA and 0.5 nA for the highest value of UEV (+5 V) and when either LG, MG or HG is selected, respectively. The measured data can be acquired in real-time with LabView software, which allows the real-time monitoring of the photocurrents for individual elements in the photodetector both through a numeric and graphical display. The light intensity can be defined by 8 digital outputs allowing 256 light intensity increments/steps from 0 to a maximum defined (by the lamp's manufacturer) light intensity. This LCFP can be used in industry to make quality control, e.g., when different test conditions are applied to the optical sensors/photodetectors and the user/customer need to quickly check if the response or performance is acceptable or resulted on any significant drifts. All these features combined with the low-cost under 1400 € makes this LCFP a suitable tool to quickly evaluate the performance of optical sensors/photodetectors., This work was sponsored by the Brazilian agency National Council of Scientific Research (Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq) under the grant 400110/2014-8: Ciência sem Fronteiras/Chamada de projetos MEC/MCTI/CAPES/CNPQ/FAPS – Bolsa Pesquisador Visitante Especial (PVE) 2014.

This paper presents the statistical analysis applied into the shape of microlenses (MLs) for validating the high-reproducibility feature of their fabrication process. The MLs were fabricated with the AZ4562 photoresist, using photolithography and thermal reflow processes. Two types of MLs arrays were produced for statistical analysis purposes: the first with a cross-sectional diameter of 24 μm and the second with a cross-sectional diameter of 30 μm, and both with 5 μm spacing between MLs. In the case of 24 μm diameter arrays, the measurements showed a mean difference in diameter of 2.78 μm with a standard deviation (SD) of 0.22 μm (e.g., 2.78 ± 0.22 μm of SD) before the reflow, and 2.34 ± 0.35 μm of SD after the reflow. For the same arrays, the mean difference in height obtained was, comparatively to the 5.06 μm expected, 0.76 ± 0.10 μm of SD before the reflow and 1.91 ± 0.15 μm of SD after the reflow, respectively. A mean difference in diameter of 2.64 ± 0.41 μm of SD before the reflow, and 1.87 ± 0.34 μm of SD after the reflow was obtained for 30 μm diameter MLs arrays. For these MLs, a mean difference in height of 0.71 ± 0.12 μm of SD before the reflow and 2.24 ± 0.24 μm of SD after the thermal reflow was obtained, in comparison to the 5.06 μm of height expected to obtain. These results validate the requirement for reproducibility and opens good perspectives for applying this fabrication process on high-volume production of MLs arrays., This work was fully supported by the Portuguese Foundation for Science and Technology under the project FCT/ PTDC/EEA-ELC/109936/2009.

This paper presents optical filters for integration on stereoscopic image sensors. The filters must cover each one of primary colors within the visible, in order to yield a passband around the respective wavelengths. Dielectric materials based on SiO2 and TiO2 were used due to their compatibility with silicon. The best simulation with only 3 dielectric layers resulted in optical filters with full width at half maximum (FWHMs) of 79, 95 and 124 nm and central wavelengths of 456, 529 and 605 nm, respectively.

This paper presents glassy films of lithium phosphorus oxynitride electrolyte with an amorphous structure and improved ionic conductivity suitable for solid‐state batteries. The films of lithium phosphorus oxynitride electrolyte were obtained by deposition using the RF sputtering technique in a reactive N2 atmosphere. The measurements showed films with ionic conductivities in range of 10− 7–10− 6 S·cm− 1, for temperatures between 22 °C and 43 °C. The depositions were done at several pressures (0.03 Pa, 0.7 Pa and 1 Pa) and for RF applied powers of 150 W and 200 W, in order to evaluate the best deposition set‐point. The highest ionic conductivity of 10− 6 S·cm− 1 was measured under a practical room temperature of 35 °C on the best films. These results are comparable with the related state‐of‐the‐art., Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-ELC/114713/2009, SFRH/BD/78217/2011.

The increasing miniaturization of electronic devices requires the miniaturization of devices that provide energy to them. Autonomous devices of reduced energy consumption are increasingly common and they have benefited from energy harvesting techniques. However, these devices often have peak power consumption, requiring storage of energy.This chapter presents the fabrication and characterization of thin-films for solid-state lithium battery. The solid-state batteries stand out for the possibility of all materials being solid and therefore ideal for microelectronics fabrication techniques. Lithium batteries are composed primarily of three materials, the cathode, the electrolyte and the anode. The positive electrode (cathode) and negative (anode) have high electrical conductivity and capacity for extraction and insertion of lithium ions. The electrolyte’s main features are the high ionic conductivity and high electrical resistivity. The materials chosen for the battery are lithium cobalt oxide (cathode), lithium phosphorus oxynitride (electrolyte), and metallic lithium (anode).The lithium cobalt oxide cathode (LiCoO2) was deposited by RF sputtering and characterized using the XRD, EDX, SEM techniques, and electrical resistivity. Fully crystalline \({\mathrm{LiCoO}}_{2}\) was achieved with an annealing of \(65{0}^{\circ }\mathrm{C}\) in vacuum for 2 h. Electrical resistivity of \(3.7\,\Omega \cdot \)mm was achieved.The lithium phosphorus oxynitride electrolyte (LIPON) was deposited by RF sputtering and characterized using the techniques EDX, SEM, ionic conductivity, DSC, and TGA. Ionic conductivity of \(6.3 \times 1{0}^{-7}\,\mathrm{S} \cdot {\mathrm{cm}}^{-1}\) for a temperature of \(2{6}^{\circ }\mathrm{C}\) was measured. The thermal stability of LIPON up to \(40{0}^{\circ }\mathrm{C}\) was also proved.The metallic lithium anode (Li) was deposited by thermal evaporation and its electrical resistance measured at four points during the deposition. Resistance of about 3. 5 Ω was measured for a thickness of 3 μm. The oxidation rate of the lithium in contact with the ambient atmosphere was evaluated. The patterning process of the battery was developed by means of shadow masks.

This chapter presents a wireless interface for intra-vehicle communications (data acquisition from sensors, control, and multimedia) at 5.7 GHz. As part of the wireless interface, a RF transceiver was fabricated in the UMC 0.18 µm RF CMOS process and when activated, it presents a total power consumption of 23 mW with the voltage-supply of 1.5 V. This allows the use of only a coin-sized battery for supplying the interface. The carrier frequency can be digitally selectable and take one of 16 possible frequencies in the range 5.42-5.83 GHz, adjusted in steps of 27.12 MHz. These multiple carriers allow a better spectrum allocation and at the same time will improve the channel capacity due to the possibility to allow multiple accesses with multiple frequencies.

The introduction of nanotechnology opened new horizons previously unattainable by thermoelectric devices. The nano-scale phenomena began to be exploited through techniques of thin-film depositions to increase the efficiency of thermoelectric films. This chapter reviews the fundamentals of the phenomenon of thermoelectricity and its evolution since it was discovered in 1822. This chapter also reviews the thermoelectric devices, the macro to nano devices, describing the most used techniques of physical vapor depositions to deposit thermoelectric thin-films. A custom made deposition chamber for depositing thermoelectric thin films by the thermal co-evaporation technique, where construction issues and specifications are discussed, is then presented. All the steps for obtaining a thermoelectric generator in flexible substrate with the custom deposition chamber (to incorporate in thermoelectric microsystems) are described. The aim of thermoelectric microsystem relays is to introduce an energy harvesting application to power wireless sensor networks (WSN) or biomedical devices. The scanning probe measuring system for characterization of the thermoelectric thin films are also described in this chapter. Finally, a few of the prototypes of thermoelectric thin films (made of bismuth and antimony tellurides, \({\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}\), and \({\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}\), respectively) obtained by co-evaporation (using the custom made deposition chamber) and characterized for quality assessment are dealt with. All the issues involved in the co-evaporation and characterization are objects of analysis in this chapter.

This paper presents a low-cost technology for fabricating optical filters arrays tuned for the primary colors. The fabrication process presented in this paper is intended for directly printing the optical filters into a transparent flexible substrate (acetate). The target application of these optical filters is for enabling the acquisition of multicolor stereoscopic images with a sensor made in CMOS technology.

Solid-state thermoelectric generators (TEGs) based on the Seebeck effect to convert temperature gradients, ΔT [K], into electrical energy are being used in an increased number of stand-alone microsystems applications. These generators are composed by at least one pair of p- and n-type thermoelectric elements with high figures-of-merit, ZT, to perform such a conversion. The exact behavior knowledge of generators is mandatory in order to decide the most suitable for the target application. The focus of this paper is to present a methodology to characterize thermoelectric generators, by measuring their behavior for different types of loads. The measurements were done with the help of commercial thermoelectric generators (thermoelectric modules TEC1-12707) and a measurement setup composed by a controlled hot-plate, a controlled cooling fan (above an heat dissipator), a set of two thermistors for measuring the temperature, a personal computer with the data acquisition board model NI USB-6009 and the LabView software from National Instruments for acquiring the measures and for controlling both the hot-plate and the cooling fan. The thermoelectric modules TEC1-12707 was selected due to its compact size (e.g., 40 mm × 40 mm) and because it can withstand temperatures up to 450 K without degrading the quality of measurements. A SPICE model for thermoelectric modules TEC1-12707 was also obtained: an open-circuit voltage of Vopen = 53.17 × ΔT [mV] and an internal resistance of R0 = 3.88 Ω with a tolerance of ΔRint = 0.13 Ω such that Rint = R0 ± ΔRint = 3.88 ± 0.13 Ω. The measurements done under the maximum output power delivery condition (for the maximum temperature gradient of ΔT = 51 °C) resulted in the maximum output power of Pout = 500 mW, as well as in the output current and voltage of Iout = 357 mA and Vout = 1.40 V, respectively. The load resistance of 3.92 Ω (Vout/Iout) is also in accordance with the measurements because it is located in the range [μ − σ, μ + σ] Ω, where μ = R0 = 3.88 Ω and σ = ΔRint = 0.13 Ω. An Agilent multimeter model 34410A with 6½ digits was used for measuring the voltages at the TEG’s output and the respective currents.

This paper presents an approach for generating a well-defined cooling pattern over an area of tissue. An array of solid-state microcoolers is used, which could be included in a probe that provides local cooling. This medical instrument can be used for removal of scar tissue in the eye or for the rapid stopping of bleeding due to micro-cuts, which makes it a useful tool to medical doctors and could make surgery more secure to the patient. The array of microcoolers is composed of 64 independent thermo-electric elements, each controlled using an integrated circuit designed in CMOS. The independent control allows the flexible programming of the surface temperature profile. This type of control is very suitable in case abrupt temperature steps should be avoided. Cooling by lateral heat flow was selected in order to minimize the influence of heat by dissipation from the electronic circuits. Moreover, a thermo-electric component with lateral heat allows fabrication of the cooling elements using planar thin-film technology, lithography and wet etching on top of the silicon wafer. This approach is potentially CMOS compatible, which would allow for the fabrication of the thermo-electric elements on top of a pre-fabricated CMOS wafer as a post-process step. Each pixel is composed of thin-films of n-type bismuth telluride, Bi2Te3 and p-type antimony telluride, Sb2Te3, which are electrically interconnected as thermocouple. These materials have excellent thermoelectric characteristics, such as thermoelectric figures- of-merit, ZT, at room temperatures of 0.84 and 0.5, respectively, which is equivalent to power-factors, PF, of 3.62 9 10-3 W K-1 m-2 and 2.81 9 10-3 W K-1 m-2, respectively. The theoretical study presented here demonstrates a cooling capability of 15 C at room temperature (300 K & 27 C). This cooling performance is sufficient to maintain a local tissue temperature at 25 C, which makes it suitable for the intended application. A first prototype was successfully fabricated to demonstrate the concept., Fundação para a Ciência e a Tecnologia (FCT) - FCT/PTDC/EEA-ENE/66855/2006 project.

This chapter cover the following topics: • the focus and application of the wireless sensor network; • the implications of the radio system; • the test bed implementation of the proposed low cost wireless sensors networks; • the wireless link power budget, coding and data recovering; • performance metrics of the wireless sensors networks; • cost analysis versus other technologies (wired and emerging wireless).

This paper presents a receiver for operation in the 433 MHz ISM band. The selected architecture explores the super regeneration phenomena to achieve a high sensitivity for applying in wireless implantable microsystems. This radio frequency (RF) chip can be supplied with a voltage of only 3 V for demodulating signals with powers in the range [ 100, 40] dB. The codulation (modulation and coding) scheme of the binary data is a variation of the Manchester code combined with OOK (on/off keying) modulation. The AMIS 0.7 µm CMOS process was selected for targeting the requirement to fabricate a low cost receiver, whose prototype was integrated in a die with an area of 55 mm2. Also, this receiver is fully compatibility with commercially transmitters for the same frequency.

This paper describes a low-power/low-voltage CMOS wireless interface (CMOS-WiI) at 5.7 GHz with dry electrodes for congnitive networks. The electrodes are 4 X4 microtip arrays and acquire electroencephalogram (EEG) signals in key- points for processing. The CMOS-WiI was fabricated in a UMC 0.18 μm RF CMOS process and its total power consumption is 23 mW with a voltage-supply of only 1.5 V. The carrier frequency is digitally selectable and it can be one of 16 possible values in the range 5.42-5.83 GHz, with 27.12 MHz steps. These multiple carriers allow a better spectrum allocation as well as the acquisition, processing and transmission of high-quality EEG signals from 16 electrode arrays. The microtips array was fabricated through bulk micromachining of a 〈100 〉-type silicon substrate in a potassium hydroxide solution and avoids long subject preparations for EEG data acquisition. The reactive sputtering of iridium dioxide (IrO) on the surface of the array guarantees its biocompatibility. The fabrication process was trimmed in a way that each microtip presents solid angles of 54.7° , a width in the range 150-200 μm, a height of 100-200 μm, and a microtip interspacing of 2 μm. The microtips array coated with IrO together with the CMOS-WiI permit the remote monitoring of EEG signals from freely-moving subjects.

This paper presents a radio-frequency (RF) transceiver for operation in the 2.4 GHz ISM band. The RF CMOS transceiver can be supplied with only 1.8 V, and it was designed to establish wireless links for distances up to 10 m, for a maximum baud-rate of 250 Kbps with a Bit Error Probability less than 10−6. The transmitter can deliver a output power of 0 dBm with a consumption of only 11.2 mW, while the receiver has sensitivity of −60 dBm and consumes only 6.3 mW. The goal of RF CMOS transceiver is for co-integration with sensors in the same die using microsystems techniques. The target application of such microsystems is in wearables (e.g., in wireless electronic shirts) for measuring biomedical data of patients. The wireless electronic shirt (WES) measures the heart rate and the respiratory frequency, and at the same time it allows patients to maintain their mobility.

This paper presents a implantable wireless microsystem concept for operation in the 433 MHz ISM band. The proposed microsystem is composed by two independent subsystems: the electrostimulation and the radio-frequency (RF) subsystems. The electrostimulation part is a silicon box with groves to pass the nerves to be stimulated. The cover of the silicon box contains electrodes for electrical contacting with the nerves. Wafer-level packaging (WLP) techniques will allow the joining of the RF and the electrostimulation subsystems. The target of this implantable microsystem is for RF reception at 433 MHz of user commands to activate the micturition function and the erection (on males) patients. The expected microsystem area will be of 5×5mm2.

This focus of this chapter is the presentation of micro and nanodevices for thermoelectric converters. Examples of applications for these converters are (1) in the conversion of electrical energy from temperature gradients and (2) in cooling devices. These converters are of solid-state type and use pairs of thermoelectric p- and n-type materials, which were obtained by thin-films depositions. In this context, issues such the fabrication and characterization details of materials are discussed. The materials selected to serve as p- and n-type structures were the antimony telluride (Sb2Te3) and the bismuth telluride (Bi2Te3). The thin-films depositions of both Bi2Te3 and Sb2Te3 materials require a precise controlled process to achieve the highest possible thermoelectric figure-of-merit, ZT, and at the same time to achieve the desire composition. This goal is achieved with the co-evaporation of antimony (Sb)/bismuth(Bi) and telluride (Te) technique. It is also analyzed the influence of the parameters involved in the depositions (e.g., the temperature which the substrate is subjected, and the evaporation rates of Sb/Bi and Te), and their impacts in the final composition of Sb2Te3 and Bi2Te3 thin-films. Advanced issues and trends related to the fabrication of super-lattices for use in thermoelectric converters are also presented in this chapter.

This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3), which were deposited using co-evaporation. The measurements on selected samples of Bi2Te3 and Sb2Te3 thin films indicated a Seebeck coefficient in the range of 90–250 μV K−1 and an in-plane electrical resistivity in the range of 7–17 μÄ m. The measurements also showed TE figures-of-merit, ZT, at room temperatures (T = 300 K) of 0.97 and 0.56, for thin films of Bi2Te3 and Sb2Te3, respectively (equivalent to a power factor, PF, of 4.87 mW K−2 m−1 and 2.81 mW K−2 m−1). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO2), an electrolyte of lithium phosphorus oxynitride (LixPOyNz, known as LiPON) and a cathode of lithium cobaltate (LiCoO2, known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper., This work was fully supported by FCT/PTDC/EEA-ENE/66855/2006 project.

This chapter introduces the concept of wireless interface, followed by the discussion of the fundamental items, concerning the fabrication of microsystems comprising low-power devices. Using as example, a design of a RF transceiver the frequency of 2.4 GHz and fabricated using a UMC RF CMOS 0.18 µm process, it will be discussed the main issues in the design of RF transceivers for integration in wireless microsystems. Then, it will be presented two biomedical applications for wireless microsystems: the first is a wireless EEG acquisition system, where it is presented the concept of EEG electrode and the characterisation of iridium oxide electrodes. The other application, is a wireless electronic shirt to monitoring the cardio-respiratory function. The main goal of these applications, is to improve the medical diagnostics and therapy by using devices which reduces healthcare costs and facilitates the diagnostic while at the same time preserving the mobility and lifestyle of patients.

This paper describes a CMOS interface for shortrange wireless sensor networks (CMOS-SRWSN interface). The sensor interface is composed of a sensor readout, electronics for processing and control, a memory, a radio-frequency CMOS transceiver for operation in the 2.4-GHz industrial, scientific, and medical bands, and a planar antenna. The receiver has a sensitivity of −60 dBm and consumes 6.3 mW from a 1.8-V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW. The application of the CMOS-SRWSN interface is in the automotive industry for the reduction of cables and to support the information, communication, and entertainment systems in cars..

A technique for IC-compatible fabrication of a planar (in-plane) thermoelectric (TE) power generator using a thermopile composed of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) thin-films is presented. The research demonstrates that the thermal co-evaporation of bismuth/antimony (Bi/Sb) and telluride (Te) is the most suitable deposition technique. The measurements showed TE performance properties of the deposited thin-films that are comparable to those reported for the same materials in the bulk form. The measurements showed absolute values of the Seebeck coefficient in the range 91–248 VK−1, an electrical resistivity in the 7.6–39.1 m range and a thermal conduction between 1.3 and 1.8Wm−1 K−1. The best resulting figures-of-merit, ZT, at room temperatures were 0.97 and 0.56 (equivalent to power-factors, PF, of 4.87×10−3 and 2.8×10−3WK−1m−2) for the Bi2Te3 and Sb2Te3 thin-films, respectively. The IC-compatibility and the dependence of the TE performance on technological details, such as photolithography and wet etching used for patterning the thin-films have also been investigated. The converter dimensions for best performance were analysed and a prototype of a planar TE power generator was fabricated.

This paper presents a solution for energy microgeneration through energy harvesting by taking advantage of temperature differences that are converted into electrical energy using the Seebeck effect. A thermoelectric microconverter for energy scavenging systems that can supply low-power electronics was fabricated using thin films of bismuth and antimony tellurides. Thin films of n-type bismuth (Bi2Te3) and p-type antimony (Sb2Te3) tellurides were obtained by thermal coevaporation with thermoelectric figures of merit (ZT) at room temperature of 0.84 and 0.5 and power factors (PF × 10−3 [W · K−1 · m−2]) of 4.87 and 2.81, respectively. The films were patterned by photolithography and wet-etching techniques. The goal for this thermoelectric microconverter is to supply individual electroencephalogram (EEG) modules composed by an electrode, processing electronics, and an antenna, where the power consumption ranges from hundredths of microwatts to a few milliwatts. Moreover, these wireless EEG modules allow patients to maintain their mobility while simultaneously having their electrical brain activity monitored., Portuguese Foundation for Science and Technology - Project FCT/PTDC/EEA-ENE/66855/2006

This paper presents a new type of dry electrodes for acquisition of biopotentials and stimulation. These dry electrodes are composed by 16 microtip structures (by forming an array of 4×4 microtips), which were fabricated through bulk micromachining of a 100 -type silicon substrate in a potassium hydroxide (KOH) solution. The fabrication process was trimmed in a way that each microtip presents solid angles of 54.7◦, a width in the range 150–200 m, a height of 100–200 m, and an inter-microtip spacing of 2mm. The electrodes have a thin layer (obtained by reactive DC-sputtering) of iridium oxide (IrO) to improve the contact with the skin. These dry electrodes penetrate the outer skin layer (i.e. stratum corneum that is 10 mthick) to allow a direct contact with the electrolyte fluids of the inner skin layers. Thenewelectrode avoid the use of conductive gels and reduce the skin preparation time in EEG experiments, whichmaytake about 45 min for a set of 32 standard silver/silver chloride (Ag/AgCl) electrodes. The electrode–electrolyte impedance spectrometry (IS) of the IrO thin-films was performed in a saline solution, 0.9% concentration by weight, to mimic the electrode–tissue interface. The IS measured results for the IrO coatings were comparable to the results observed for the standard Ag/AgCl electrodes. The new dry microtips array constitutes an inexpensive, low resistance and mechanically robust alternative electrode for non-invasive biopotential recording/stimulation with fast application on skin., Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/21529/2005

This paper presents a new wireless microsystem for for use in urology. This microsystem is composed by two parts: the electrostimulation and the radio-frequency (RF) subsystems. The electrostimulation part is a silicon box with groves to pass the nerves to be stimulated. Above the stimulation box is putted a cover containing electrodes to do the electrical contacts with the nerves. Using wafer-level packaging (WLP) techniques the RF and the electrostimulation parts are joined together. This implantable microsystem allows the reception of RF signals with user commands to activate the micturition function and the penian erection (on males) patients. The microsystem has an expected area of 5×5 mm2.

This paper presents the development of an integration technology that offers a breakthrough solution for the industrial manufacturing of flexible smart materials with optical sensing features. Subsequently, it aims the development of a flexible substrate, or foil, in which optical waveguides and sensing elements are integrated in line during the manufacturing process of the substrate itself. This artificial and flexible optical sensing foil can then be applied to regular or irregular surfaces, enabling a quasi-distributed strain map. Fabrication, using industrial processes, and characterization of a polymeric foil able to sense, gather and send sensitive information for remote analysis is explored. The propose smart material uses Fiber Bragg Grating sensors embedded in standard laminated polymeric sheets used in different industries, as automotive or aeronautic. The definition of the whole integration process as well as the PVC paste custom formulation for better integration results is described. The presented optical sensor incorporated in the polymeric foil is fully functional with high sensitivity, 0.6 pm/µstrain, measuring deformation, up to 1.2 mm.

This paper presents a solution to increase the nominal lifetime of batteries in laptops. New thin-film materials offer potentially greater efficiencies when converting heat to electricity using the thermoelectric effect. Applied to microprocessors, this technology can mitigate a number of critical problems as the critical amount of heat produced by laptops. The use of a thermoelectric scavenging microsystem based on the Seebeck effect can address this problem, by extracting waste heat from a high-end microprocessor, converting the heat to electricity using thin-film technology in silicon compatible materials. Applying a thermoelectric micro converter (that was fabricated using thin-films of bismuth and antimony tellurides) to a temperature gradient of 60 °C, it is possible to obtain an efficiency of 3% and increase in the same amount, the lifetime of batteries.

A thermoelectric planar microcooler was fabricated on top of a flexible substrate, using Bi 2 Te 3 and Sb 2 Te 3 thermoelectric elements. Finite element analysis and theoretical calculations previewed a temperature drop of 16 oC in the cold area of the device. Bi 2 Te 3 and Sb 2 Te 3 materials were deposited by thermal co-evaporation on a kapton substrate, 12 μm thick. Photolithography and wet-etching were used to patterning the structures. Devices were tested by infrared imaging and results demonstrated that microsystems technology can be applied in the fabrication of thermoelectric microcoolers.

Improved microstructures based on thin-films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) to convert temperature differences in electricity are presented. The microstructures are obtained by thin-film deposition, applying the co-evaporation method to the bismuth/antimony and telluride materials. Measurements demonstrated the superior thermoelectric features of the obtained films when compared with the most recent thermoelectric thin-film deposition. Measurements show that the deposited films present thermoelectric properties comparable to those reported for the same materials in bulk form, as is the case of the materials used in conventional macro-scale Peltier modules. The absolute values of the Seebeck coefficient are in the range 150–250 mVK21 and the in-plane electrical resistivity is in the 7–15 mVm range. Measurements for the Bi2Te3 and Sb2Te3 films also show figures of merit at room temperatures of 0.84 and 0.5, and power factors of 4.87 and 2.81 mWK22 m21, respectively. These microstructures are used for the fabrication of thermoelectric microgenerators to supply stand-alone microsystems with power consumption that ranges from cents of mW to a few mW., This work was fully supported by the Portuguese Science Foundation FCT/PTDC/EEA-ENE/66855/2006 project.

This paper presents RF microsystems constituted by low-power devices for use in wireless sensors networks. As it is expected, the major emphasis is given to the fabrication of RF transceivers for integration in these microsystems. Features like low-power and low-voltage operations are discussed, at the same time are presented RF transceivers for the frequencies of 433 MHz, 2.4 GHz and 5.7 GHz, in order to comply with mandatory issues of WSN, e.g., working independently from a human operation, management and maintenance. Another reason for this, is the suitableness of these wireless microsystems to use thermoelectric energy scavenging systems.

This paper presents a low-power/low-voltage frequency synthesizer for the frequency of 2.4 GHz, which were designed and fabricated in a standard 0.18 µm CMOS process. This synthesizer is based on a Phase-locked Loop (PLL) with a integer divider in the feedback loop and for a voltage supply of only 1.8 V, it presents a total power consumption of 3.4 mW. The power consumptions for the Voltage-controlled oscillator, phase-frequency difference/charge-pump and for the divider are 2 mW, 1 mW, 420 µW, respectively. The PLL is very fast, e.g., it takes only 1.6 µs to lock, which makes it a perfect companion for devices where frequency hops must be done very quickly.