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Smart factories must speed up their processes to face new manufacturing challenges and, at the same time, demonstrate an extremely high degree of flexibility to reduce production costs and time. This kind of issues can be addressed by the cooperation between humans and robots in a mixed human-robot working environment. Robots have the compelling advantage of spatial precision and repeatability as well as the capability of applying defined forces. Humans, on the other hand, are especially skilled at complex manipulations and adapting to changing task requirements. In this complicate scenario of co-shared workplace and continuous human-robot interaction, safety strategies are a key requirement to avoid possible injuries to humans or fatal accidents. This chapter proposes a systemic approach to respond to these requirements. The approach merges and manages multiple sensing sources, redundant transmission protocols and software decision mechanisms, aiming to guarantee a continuous and reconfigurable co-share scenario that enables an operative interaction between human workers and robots in a controlled and safe environment. Furthermore, new technological solutions and innovative methodologies are presented for the definition of a safer workplace in human-robot interaction scenarios.

Pilots and astronauts can generally experiment high stress during their working activity since they have to manage in a short time a large number of tasks usually in extreme conditions. Moreover, in case of fighter pilots, the management of the stress is even more crucial and it can represent the first cause of accident or death. In this scenario, the real time monitoring of different parameters such as heart rate, ventilation rate, oxygen saturation, and muscle reactivity represents a unique method to collect the information that can activate safe procedures and reduce the danger or train to manage these situations. At the same time, it is fundamental to provide sensing systems that have to minimize the discomfort of the pilot. The usage of bulky devices in fact can hinder the normal activity of the pilot or even can result dangerous for his safeness. For this reason, the implementation of fully wearable sensing systems are mandatory in order to create a smart invisible network that does not affect the pilot movements. In this work, we present a wireless, fully wearable wristband equipped with ultra-thin flexible PVDF-TrFE pressure sensor and highly stretchable strain gauge sensors. The devices are deployed inside or above the wristband avoiding any sense of discomfort or stiffness of the arm. The wearable system can detect the cardiac activity of the pilot without the need of a tight contact with the skin and the fine movements of the hand can be collected to determine the reactivity of the pilot during the flight.

In this paper we report on recrystallized amorphous hydrogenated germanium (a-Ge:H) thin film on polyimide to fabricate flexible near infrared (NIR) light sensitive resistors that can be used in flexible electronics. In this work we investigate the effect of pulsed excimer laser annealing of a-Ge:H thin films for fabrication of low temperature photo-detectors operating in the NIR.

High n-type doping in germanium is essential for many electronic and optoelectronic applications especially for high performance Ohmic contacts, lasing and mid-infrared plasmonics. We report on the combination of in situ doping and excimer laser annealing to improve the activation of phosphorous in germanium. An activated n-doping concentration of 8.8 x 10(19) cm(-3) has been achieved starting from an incorporated phosphorous concentration of 1.1 x 10(20) cm(-3). Infrared reflectivity data fitted with a multi-layer Drude model indicate good uniformity over a 350 nm thick layer. Photoluminescence demonstrates clear bandgap narrowing and an increased ratio of direct to indirect bandgap emission confirming the high doping densities achieved.

Flexible sensors are gaining increasing interest in a number of applications, including biomedical, food control, domotics and robotics, having very light weight, robustness and low cost. Low temperature polycrystalline silicon (LTPS) technology is particularly attractive for such applications, since LTPS TFTs show excellent electrical characteristics, good stability and offer the possibility to exploit CMOS architectures. Then, as examples of flexible sensing systems, we present a tactile sensor for robotic applications and a pH sensor for biomedical applications. The present results can pave the way to advanced flexible sensing systems, where sensors and local signal conditioning circuits can be integrated on the same flexible substrate.

In this work we study the impedance behaviour of microelectrodes arrays nanostructured with different patterns by using a dual beam focused ion beam FIB. The devices were first fabricated by embedding a metal tri-layer of Ti/Au/Cr, 250 nm thick, into two ultra-flexible polyimide layers, reaching a final thickness of 8 ?m. Then, different patterns of holes (diameters from 100 to 500 nm) were produced by milling single pixels at a current of ~10 nA at increasing pitch (up to 3000 nm) and at different dwell time (up to 12 ms). The adopted milling parameters (in particular the single pixel milling strategy at rather high current) allow to obtain a nano-pattern onto an electrode area of 150 × 150 ?m in a reasonably short time (from 10 s to 5 min for each electrode). Other patterns were also investigated in which the FIB was scanned uniformly to induce surface roughening. Electrochemical impedance spectroscopy analysis was performed in vitro in a KCl solution 100 mM, by using a potentiostat VersaSTAT 4 by PAR, finding an average impedance reduction of about one order of magnitude respect to the impedance of the flat electrodes. © 2014 Elsevier B.V. All rights reserved.

In this work we propose to implement some innovative wearable technologies to manage safe interaction between astronauts and robots for specific dangerous tasks of maintenance such as those spent in long extra-vehicular activities. In particular, among the different technologies used in terrestrial applications of human machine interface, we analyse the possibility to adopt high sensitive device based on strain gauges that can be deployed inside the astronaut suite, guaranteeing a high level of comfort and a real-time monitoring of the movements of the worker. Moreover, flexible electronics is proposed as ad hoc technology to integrate part of the electronics inside the wearable smart garments. Finally, wireless communication with high redundant protocols and wireless sensor network are taken into account in order to favour a continuous dialogue between the two parts.

A key characteristic of semiconductor nanowires (NWs) is that they grow on any substrate that can withstand the growth conditions, paving the way for their use in flexible electronics. We report on the direct growth of crystalline silicon nanowires on polyimide substrates. The Si NWs are grown by plasma-enhanced chemical vapor deposition, which allows the growth to proceed at temperatures low enough to be compatible with plastic substrates (350 degrees C), where gold or indium are used as growth seeds. In is particularly interesting as the seed not only because it leads to a better NW crystal quality but also because it overcomes a core problem induced by the use of Au in silicon processing, i.e. Au creates deep carrier traps when incorporated in the nanowires.

In this work we present a flexible pyroelectric sensor composed by a PVDF-TrFE capacitor realized on ultra-thin polyimide film (5 mu m thick), integrated with a n-channel low temperature polysilicon thin film transistor also fabricated on ultra-thin polyimide (8 mu m thick). Exploiting a multi-foil approach, the pyroelectric capacitors and the transistors were attached one over the other reaching a final thickness of about 15 mu m. The bottom contact of the sensor capacitance was connected to the gate of the transistor by a silver ink, while, for bias and load resistances, we used external elements. The active sensor area was defined by a circular capacitor with a diameter of about 2 mm. In order to enhance PVDF-TrFE pyroelectric properties, an external stepwise voltage was applied to the structure up to values of 160 V at a temperature of about 80 degrees C. The devices were then tested, at different working frequencies (up to 800 Hz) under a specific infrared radiation provided by a He-Ne laser, with a wavelength of 632 nm and maximum power of 5 mW. An output signal of tens of millivolt was observed at 10 Hz, exploiting the pre-amplification of polysilicon thin film transistor.

In this paper we present the design and fabrication of a humidity sensor on ultra thin (8 μm) flexible polyimide substrate. The ultra thin flexible substrate can be preserved also when a read-out electronic interface is integrated by using Polycrystalline Silicon Thin Film Transistors technology. The sensor device is a capacitor where a thin layer of [bis(benzo cyclobutene)] is used as a dielectric sensitive material between two metal electrodes. The electrode layout has been designed with the aid of numerical simulations in order to optimize the sensor performances. The fabricated sensor has shown sensitivity to relative humidity of 0.38%/RH% and a linearity of 0.996 in the range of 10–90 RH%. Furthermore, measurements regarding the sensor response time, different bending and bias voltage effects have been performed.

We have fabricated bottom contact pentacene TFTs on flexible polyimide substrate and silicon substrate using different passivation layers in order to reduce the electrical instability of pentacene devices, induced by water diffusion in the film, as evidenced by electrical measurements under different environments. Experimental data show that parylene passivation layer does not introduce appreciable degradation of device characteristics and allows standard lithographic process, but it is not an effective barrier for water diffusion. The encapsulation of pentacene TFTs with an additional acryl layer does not reduce the device sensitivity to the water, whereas devices encapsulated by a parylene/acryl/aluminum triple layer do not show increase of transfer characteristics hysteresis when measured in air.

In this work, we investigated self-heating related instability in polysilicon thin film transistors (poly-Si TFTs) fabricated on polyimide (PI) substrates. Indeed, when Joule heating becomes relevant, the temperature of the active layer can substantially rise, since the devices are fabricated on thermally insulating substrates. As a result, electrical instability is triggered and attributed to the generation of interface states, due to the Si–H bond breaking, and charge trapping into the gate insulator. In addition, by using 3-dimensional numerical simulations, coupling the thermodynamic and transport models, we analyzed the temperature distribution of the device under operating conditions and found that self-heating is more severe for devices fabricated on plastic substrates.

In this work we present a flexible read-out circuit embedded with a POSTFT (Piezoeletric Oxide Semiconductor TFT) tactile sensor for electronic skin application. The circuit has been fabricated using n-mos LTPS (Low Temperature Poly-Silicon) technology, integrated on a flexible substrate of PI (PolyImide). A cascade of two common source amplifiers, engineered to provide enhanced output, composes the schematic. The tactile sensor has been designed adopting an extended gate configuration to provide higher robustness to the mechanical solicitations. The optimization of the piezoelectric properties of the device has been accomplished through a well-established poling procedure, reaching piezoelectric coefficient of 45 pC/N. Once fabricated, the sensor has been detached from the rigid carrier and bonded to a flexible PCB for testing purpose. A mini-shaker has been used to electromechanically stimulate the sensor and verify the performance, obtaining output signal up to 2.5Vp-p for a mechanical stimulus of 1N @200Hz.

Today ultra-flexible electronic devices can be successfully embedded in smart clothes, integrated in transparent displays, hidden in tubular structures to increase the numbers of sensors in an urban space or in a specific environment, thus enhancing the interaction of a person and maximizing the shared amount of available information. Coupling this technology with nanostructures based sensing devices is a further step to revolutionize the idea of distributed smart objects. Polysilicon based materials on plastic is a mature technology to fabricate electronic read-out circuits suitable to manage and control the signals coming from sensors of different nature, conceiving new applications and wearable solutions. Moreover, the possibility of directly integrating active devices together with sensors reduces issues related to signal to noise ratio, providing a local preamplification.

In this work we investigate the electromechanical behavior of a flexible piezoelectric sensor, based on Polyvinylidene-fluoride-trifluoroethylene (PVDF-TrFE) capacitor fabricated on ultra-thin polyimide film (5 µm thick). The piezocapacitor has been integrated with a high mobility p-channel organic thin film transistor, made on polyethylene naphthalate (PEN, 125 µm thick), by adopting a multi-foil approach. An extensive study of the effects of the electrical and mechanical stress on the device components has been reported in order to evaluate the sensor's reliability in a real environment. Then the sensor was tested, at different working frequencies and applied forces with the intent of mimicking the human sense of touch. We believe that this device can represent a key element for a high performing electronic skin system to be deployed on humanoid robot.

Electrocorticography (ECoG) is becoming a common tool for clinical applications, such as preparing patients for epilepsy surgery or localizing tumor boundaries, as it successfully balances invasiveness and information quality. Clinical ECoG arrays use millimeter-scale electrodes and centimeter-scale pitch and cannot precisely map neural activity. Higher-resolution electrodes are of interest for both current clinical applications, providing access to more precise neural activity localization and novel applications, such as neural prosthetics, where current information density and spatial resolution is insufficient to suitably decode signals for a chronic brain-machine interface. Developing such electrodes is not trivial because their small contact area increases the electrode impedance, which seriously affects the signal-to-noise ratio, and adhering such an electrode to the brain surface becomes critical. The most straightforward approach requires increasing the array conformability with flexible substrates while improving the electrode performance using materials with superior electrochemical properties. In this paper, we propose an ultra-flexible and conformable polyimide-based micro-ECoG array of submillimeter recording sites electrochemically coated with high surface area conductive polymer-carbon nanotube composites to improve their brain-electrical coupling capabilities. We characterized our devices both electrochemically and by recording from rat somatosensory cortex in vivo. The performance of the coated and uncoated electrodes was directly compared by simultaneously recording the same neuronal activity during multiwhisker deflection stimulation. Finally, we assessed the effect of electrode size on the extraction of somatosensory evoked potentials and found that in contrast to the normal high-impedance microelectrodes, the recording capabilities of our low-impedance microelectrodes improved upon reducing their size from 0.2 to 0.1 mm. 1534-4320

In this work we present an investigation on a conductive thermoplastic nanocomposite used as flexible and stretchable strain gauge to be applied on inflatable structures for both terrestrial and extra-terrestrial applications. In particular we analysed the sensor behaviour by using an one-dimensional expansion system for increasing strain up to 5% and we studied the device changing in temperature. The strain gauge was also tested after several expansion cycles thus analysing the sensor response in time and ageing effects. Finally we tested the sensor on an inflatable naval fender in order to reproduce the sensor behaviour in real conditions.

Flexible sensors are gaining increasing interest in a number of applications, including biomedical, food control, domotics and robotics, having very light weight, robustness and low cost. Low temperature polycrystalline silicon (LTPS) technology is particularly attractive for such applications, since LTPS TFTs show excellent electrical characteristics, good stability and offer the possibility to exploit CMOS architectures. Then, as examples of flexible sensing systems, we present a tactile sensor for robotic applications and a pH sensor for biomedical applications. The present results can pave the way to advanced flexible sensing systems, where sensors and local signal conditioning circuits can be integrated on the same flexible substrate.

A fully flexible pH sensor using nanoporous ZnO on extended gate thin film transistor (EGTFT) fabricated on polymeric substrate is demonstrated. The sensor adopts the Low Temperature Polycrystalline Silicon (LTPS) TFT technology for the active device, since it allows excellent electrical characteristics and good stability and opens the way towards the possibility of exploiting CMOS architectures in the future. The nanoporous ZnO sensitive film, consisting of very thin (20 nm) crystalline ZnO walls with a large surface-to-volume ratio, was chemically deposited at 90 °C, allowing simple process integration with conventional TFT micro-fabrication processes compatible with wide range of polymeric substrates. The pH sensor showed a near-ideal Nernstian response (~59 mV/pH), indicating an ideality factor ? ~ 1 according to the conventional site binding model. The present results can pave the way to advanced flexible sensing systems, where sensors and local signal conditioning circuits will be integrated on the same flexible substrate. © 2014 AIP Publishing LLC.

Electrocorticography, thanks to its low degree of invasiveness, has received in recent years an increasing attention for chronic brain-machine interface applications. To be up to the task, electrocorticography electrode arrays can benefit from several improvements. Better recording abilities can be obtained through smaller, low impedance and high density electrodes, while conformability can provide superior adhesion to the cortex surface and lower biological impact. In this work we present an ultra-flexible and brain-conformable polyimide-based micro-ECoG array with low-impedance poly(3,4-ethylenedioxythiophene) (PEDOT)-carbon nanotube coated microelectrodes. A first in vivo validation of our device is performed on rat somatosensory cortex.

Flexible sensors are gaining increasing interest in a number of applications, including biomedical, food control, domotics and robotics, having very light weight, robustness and low cost. In order to improve signal-to-noise ratio, integration of readout electronics is crucial and several technologies are available for the fabrication of thin film transistors (TFTs) based circuits on flexible substrates. Among these technologies, the low temperature polycrystalline silicon (LTPS) is particularly attractive, since LTPS TFTs show excellent electrical characteristics, good stability and offer the possibility to exploit CMOS architectures. The different aspects for the direct fabrication of LTPS TFTs on polymer substrates are reviewed and the specific fabrication process adopted on ultrathin polyimide substrates is described in some detail. Then, as examples of flexible sensing systems, we present both chemical and physical sensors integrated with LTPS TFTs frontend electronics. The present results can pave the way to advanced flexible sensing systems, where sensors and local signal conditioning circuits can be integrated on the same flexible substrate.

In this paper we present the design and fabrication of a fully flexible sensorial system, composed of three different sensor units implemented on an ultrathin polyimide substrate of 8 μm thick. Each unit is composed by a capacitive chemical sensor integrated with readout electronics. The sensors are parallel plate capacitors with the top electrode properly patterned to allow analytes diffusion into the dielectric that acts as chemical interactive material. Three different polymers, poly(tetrafluoroethene) (PTFE), poly(methyl 2-methylpropenoate) (PMMA) and benzocyclobutene (BCB), were used as dielectrics. A ring oscillator circuit, implemented with polysilicon thin film transistors (PS-nTFT), was used to convert the capacitance variations into frequency shifts. The electronic tests show oscillating frequencies of about 211 ± 2 kHz and negligible frequency shifts under different bending radius conditions. Furthermore, system response to some alcohols concentrations (Methanol, ethanol, 1-butanol, and 1-propanol) is reported and data analysis proves that the system is able to discriminate methanol from ethanol.

Different amounts of single wall carbon nanotubes (SWCNTs) have been sprayed on amorphous silicon substrates to form Schottky barrier solar cells. The measured external quantum efficiency showed a spectral behavior depending on the SWCNT network optical transparency, presenting a maximum up to 35% at a wavelength of about 460 nm. Ultrathin network of SWCNTs acts as semitransparent electrode and forms Schottky barrier with amorphous silicon, enabling new generation low cost amorphous silicon based solar cells. Numerical simulations show a poor efficiency of SWCNT contacts in collecting holes suggesting that improvement in contact quality is needed to further improve solar cell efficiency.

We present the design and fabrication of a chemoresistive sensor array for the volatile organic compounds and gas detection. Different nanofibrous conductive polymers, produced by electrospinning technique, have been used as chemical interactive materials. Sensor array was integrated with read-out electronic circuits on flexible substrate. In order to obtain high electrical performances maintaining integration capability, on plastic materials, respect to standard c-Si CMOS technology, polycrystalline silicon thin film transistor based circuitry has been used. The performances of the fabricated sensor array have been tested with different concentrations of Methanol, Lactic acid and Ammonia.

In this paper we present the design and fabrication of two flexible sensor devices: humidity sensor and ammonia sensor integrated with electronic circuit interface on thin flexible substrate (8 mum). The transducers layout has been optimized by means of numerical simulations. A thin layer of Bisbenzocyclobytene (BCB) is used as dielectric sensitive material in humidity sensor. Conversely a mixed polymer layer based on polyaniline emeraldine base (PANi-EB) is used as sensing conductive polymer for ammonia.

In this work we show a new low-temperature polycrystalline silicon (LTPS) thin film transistor (TFT) fabrication process on polyimide (PI) layers. The PI is spun on Si-wafer used as rigid carrier, thus overcoming difficulties in handling flexible freestanding plastic substrates, eliminating the problem of plastic shrinkage with high temperature processing and allowing the use of standard semiconductor equipment. LTPS TFTs are fabricated according to a conventional non self-aligned process, with source/drain contacts formed by deposition of a highly doped Si-layer and patterned by a selective wet-etching. Laser annealing is performed providing simultaneous dopant activation and crystallization of the active layer. The maximum process temperature is kept below 350 °C. After LTPS TFTs fabrication, the PI layer is mechanically released from the rigid carrier, which can be re-used for a new fabrication process. The devices exhibit good electrical characteristics with field effect mobility up to 50 cm 2 /V s. Analysis of electrical stability and characteristics in presence of mechanical stress is also shown.

The formation of polycrystalline Si layers on flexible plastic substrates, through plasma enhanced chemical vapor deposition and excimer laser annealing, is investigated. Combining low-temperature (300 degrees C) annealing with laser dehydrogenation/crystallization produces good-quality polycrystalline silicon with a reduced shot density. By using optimal crystallization conditions it is possible to achieve a superlateral growth crystallization regime, with a grain size up to 1 mu m, and void-free material, as confirmed by the presented structural analysis. The beneficial effect of the low-temperature thermal annealing has been related to the removal of nonbound hydrogen, as supported by the elastic recoil detection analysis and IR analysis of the samples. To validate the process, we fabricated non-self-aligned polysilicon thin-film transistors (TFTs) directly on spin-coated polyimide substrates, with a maximum processing temperature of 300 degrees C and with a relatively low shot density (< 10 shots/point). The TFTs presented good electrical characteristics with an on/off ratio > 10(6), a field-effect mobility up to 65 cm(2)/V s, and a threshold voltage of 7 V. These results confirmed that the developed crystallization process is suitable to fabricate polysilicon TFTs on polymeric substrates, allowing an increased process throughput.

In this work we present a new low-temperature poly-silicon (LTPS) TFTs fabrication process, based on excimer laser annealing, on polyimide (PI) substrate. The PI is spun on Si-wafer, used as rigid carrier, thus overcoming difficulties in handling flexible freestanding plastic substrates, eliminating the problem of plastic shrinkage with high temperature processing and allowing the use of standard semiconductor equipments. LTPS TFTs are fabricated according to a conventional non self-aligned process, with source/drain contacts fabricated by deposition of a highly doped Si-layer and patterned by a selective wet-etching. Excimer laser annealing is performed providing simultaneous dopant activation and crystallization of the active layer. The maximum process temperature was kept below 350degC. After LTPS TFTs fabrication, the PI layer is mechanically released from the rigid carrier, which can be re-used for a new fabrication process. The devices exhibit good electrical characteristics with field effect mobility up to 50 cm2/Vs. Analysis of electrical stability and characteristics in presence of mechanical strain will be also shown.

SiO2-HfO2: Er3+-Yb3+ waveguide was prepared by multi-target rf-sputtering technique on silica substrate. The optical parameters were measured by an m-line apparatus operating at 543.5, 632.8, 1319 and 1542 nm. The structural properties were investigated with energy dispersive spectroscopy and Raman spectroscopy. The planar waveguide had a single-mode at 1.3 and 1.5 mum and an attenuation coefficient of 0.2 dB/cm at 1.5 mum was obtained. The 4I13/2 rarr 4I15/2 emission of Er3+ ion transition with a 42 nm bandwidth and a lifetime of 4.6 ms was observed upon excitation in the TE0 mode at 980 and 514.5 nm. Photoluminescence (PL) excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er3+ ions by co-doping with Yb3+ ions and the spectrum reported indicates that an effectual energy transfer from ytterbium to erbium ions is present. Additional work is currently under way to investigate the effect of the Er3+/Yb3+ concentration and excitation power on the Er3+ fluorescence intensity at 1.53 mum. Rib waveguide was also produced by photolithography and wet etching process. PL measurements were performed using the TE0 mode excitation on the planar system, and injecting the laser light by a 20X microscope objective in the channel on the etched system. The spectral shape of the erbium emission at 1.5 mum obtained on the channel system is equal to that obtained on the planar system. The measurements of signal enhancement when pumping Erbium ions at 980 nm are in progress.

Dual frequency plasma-enhanced chemical-vapour deposition (DF-PECVD) of silicon nitride has been investigated for the fabrication of membranes for micromechanical applications, and in particular for capacitive micromachined ultrasonic transducers (CMUTs). The use of high and low frequency plasma excitations, at 13.56 MHz and 340 KHz, respectively, allows to adjust the intrinsic stress of the thin silicon nitride films, varying the ratio between the time intervals during which the two RF power supplies are active in one cycle during the deposition process. In addition, silicon nitride films with high compactness and homogeneity, high resistivity, low porosity and conformally deposited on patterned substrates have been obtained. The optimized DF-PECVD silicon nitride has been used as structural layer and protection layer of the CMUTs.

Piezoelectric crystals, ceramics, polymers, and piezocomposite materials have long dominated the ultrasonic transducer technology, especially in medical ultrasound imaging. In recent years, thanks to the advances in microfabrication techniques, the technology of capacitive Micromachined Ultrasonic Transducers (CMUTs) has emerged as a competitive technology in the field of medical imaging.

The interfacing of a on-chip microreactor with the external world is investigated from the microfluidic point of view. A solution for coupling of input and output capillaries perpendicular on the micro-reactor plane is presented. The micro-reactor consists of a planar array of 7 x 7 metallic electrodes covered by a borofloat® glass reservoir provided with openings for the input and output capillaries having an internal diameter in the range of 220 – 500 μm on a chip of 12 x 13 mm. The reservoir has a volume of 60 μl and was manufactured by means of wet etching using a lithographically patterned Au/Cr mask. The capillaries are vertically inserted in the reservoir’s openings and leaned by means of silicone rings with cylindrical and respectively conical shape, the larger of them being glued with a silicone based adhesive. The key process steps were: cutting the rings with appropriate shape, size and contact surface; aligning and gluing the fixed rings. A functional trail of the obtained microreactor has been performed in an electrochemical set-up that allowed a continuous flow of the analyte of 10 μl / min.

A micro-cell consisting of a planar array of Au working electrodes, covered by a glass reservoir (600 nl capacity), connected with perpendicular capillaries and provided with an Ag/AgCl wire reference electrode (RE) has been manufactured. Addressed on-chip immobilization and sensing of biomolecules was demonstrated by the immobilization of histidine (HIS) tagged alkaline phosphatase (AP) under continuous flow (10 μl/min) conditions on the base of electrochemically deposited multilayer (EDM) of cysteamine modified by nitrilotriacetic acid (NTA). The presented method allows the immobilization of different biomolecules on the ready-to-use reservoir covered chip without needs of manual biomolecule deposition. Further on, the detection of analytes can be performed using the electrochemical measurements. Since the methods of biomolecule deposition and sensing are both electrochemical, this allows simplifying the production technology using cheaper detection instruments compared to prevailing present-day optical detection modes.

The silicate spin-on-glass (SOG) assisted low temperature bonding of different types of glasses on silicon and silicon compounds substrates is widely used in micromachining of analytical devices. Two silicate spin-on-glasses (SOG), potassium silicate KASIL 2130 and sodium silicate N/N CLEAR , both of them from PQ Inc., are used. Previous experiments have revealed the formation of clusters and voids in the cured glass layer, that diminishes the bonding quality. A quantitatively analysis of the bonding process in terms of work of adhesion and interfacial tensions enabled us to identify the hot points of the bonding process: the wettability of the surfaces to be bounded, the appropriate concentration of the soluble glass, the adhesion of the spin-on-glass on these surfaces in both liquid and solid state, the spun-on-glass curing process. To overcome these hot points appropriate technological steps are added to the bonding process : O 2 plasma and hot HNO 3 exposure of glass/silicon respectively silicon nitride surfaces, one minute delay of spinning after sog-deposition on the substrate, increasing up to 125°C the annealing temperature of the spun-on-glass. Smooth, uniform, reproducible glass layers, are obtained and the dependency of their thickness (ranging from 100 A to 5000 A) versus silicate concentration of the soluble glass is determined. In order to explain the clusters and voids formation, successively observations of the cured layer after the annealing treatment and after room temperature storage are performed, and show that room temperature storage of non-completely cured silicate layers leads to the formation of clusters. The effect of the concentration of the soluble silicates is qualitatively analysed, by means of optical microscopy, showing that silicate solutions having 2 -3% of wt. are suitable for bonding applications with best results when the obtained glass layer is thin enough.

The completion of the DNA sequence of several genomes, including the human one, has opened completely new scientific and technological frontiers. The huge amount of genetic information available requires the development of faster and cheaper analytical tools. This can be possible by miniaturising the analytical system itself and by the development of proper analytical procedures, involving fluidic processes. A precise genetic identifying technique is hybridization, that can be accomplished in an array format on very small bidimensional surfaces. In order to automate the fluidic process involved in the DNA hybridization, three micromachining techniques are approached by the authors team, for obtaining reservoirs with volumes ranging from 1nl to 2μl using different materials as polyimide, silicon and glass. Several configurations were proposed targeting a turbulence free fluid flow. A qualitatively fluid flow study was performed and the influence of the reservoir shape was revealed. One obtained device was tested in a Laser Induced Fluorescence detection set-up.

In order to obtain specific channels and reservoirs in glass for analytic systems, the structuring of borosilicate glass has been studied. We used wet etching in HF diluted solution for etching channels up to 150 μm depth. A mask obtained by successively wet etching of previously evaporated Au and Cr layers has been used. A thick SJR 5740 type resist has been spun-on in order to accomplish the optical transfer of the pattern. A normal underetching not larger than the depth, has been obtained when adding a small amount of nitric acid, and using an appropriate annealing process after metal deposition. Neither pinholes nor cracks have been noticed after getting an etching depth of 180 μm. Double side etching has been performed for penetrating the glass. The dependence of the etching rate vs. both HF and HNO 3 concentration is outlined together with the etched surface quality.

Erbium activated SiO 2 -HfO 2 planar waveguides, doped with Er 3+ concentrations ranging from 0.01 to 4 mol%, were prepared by sol-gel method. The films were deposited on v-SiO 2 and silica-on-silicon substrates using dip-coating technique. The waveguides show high densification degree, effective intermingling of the two film components, and uniform surface morphology. The waveguide deposited on silica-on-silicon substrates shows one single propagation mode at 1.5μm, with a confinement coefficient of 0.81 and an attenuation coefficient of 0.8 dB/cm at 632.8nm. Emission in the C-telecommunication band was observed at room temperature for all the samples upon continuous-wave excitation at 980 nm or 514.5 nm. The shape of the emission band corresponding to the 4 I 13/2 → 4 I 15/2 transition is found to be almost independent both on erbium content and excitation wavelength, with a FWHM between 44 and 48 nm. The 4 I 13/2 level decay curves presented a single-exponential profile, with a lifetime ranging between 1.1-6.6 ms, depending on the erbium concentration. Infrared to visible upconversion luminescence upon continuous-wave excitation at 980 nm was observed for all the samples. Channel waveguide in rib configuration was obtained by etching the active film in order to have a well confined mode at 1.5 μm.

SiO 2 -TiO 2 :Er 3+ -Yb 3+ waveguides were prepared by rf-sputtering technique. The active films were deposited on silica-on-silicon and v-SiO 2 substrates. The parameters of preparation were chosen in order to optimize the waveguides for operation in the NIR region with particular attention to the minimization of losses. The thickness of the waveguides and the refractive index at 632.8 and 543.5 nm were measured by an m-line apparatus. The losses, for the TE0 mode, were evaluated at 632.8 and 1300 nm. Roughness measurements were carried out by means of a stylus profilometer. The structural properties were investigated with several techniques such as Energy Dispersive Spectroscopy and Raman Spectroscopy. All waveguides were single-mode at 1550 nm. An attenuation coefficient equal or lower than 0.2 dB/cm was measured both at 632.8 nm and 1300 nm. The emission 4 I 13/2 → 4 I 15/2 of Er 3+ ion transition with a 40 nm bandwidth was observed upon excitation in the TE0 mode at 981 and 514.5 nm. Back energy transfer from Er 3+ to Yb 3+ was demonstrated by measurement of Yb 3+ emission upon Er 3+ excitation at 514.5 nm. Photoluminescence excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er 3+ ions by co-doping with Yb 3+ ions. Channel waveguides in rib configuration were obtained by etching the active film by a wet etching process. Scanning Electron Microscopy was used to analyze the morphology of the waveguides.