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This paper presents a microsystem suitable for contact-less human body temperature measurements, as well as for presence, motion and proximity detection. It consists of a 130-nm CMOS-SOI MEMS (Micro-Electro Mechanical System) thermal sensor, referred to as ``TMOS'', and its 130-nm CMOS interface circuit. The TMOS, based on a micromachined transistor, being an active device, features advantages in terms of internal gain: with optimal biasing, indeed, the TMOS achieves 274-μV/°C input-referred sensitivity at 3-cm distance and 50.33° field-of-view (FOV), outperforming thermopile detectors. The sensor and the interface circuit, featuring a chopper-stabilized-based analog readout with a 12-bit SAR ADC (Successive Approximation Register Analog-to-Digital Converter), were mounted in the same package and extensively measured: the microsystem achieves repeatability and ±0.17°C precision, thus satisfying the requirements for contact-less human body temperature measurements; furthermore, its performance as presence, motion and proximity detector was also verified.

This paper presents a novel non-imaging digital passive Infra-Red (PIR) sensing system using a CMOS-SOI-MEMS transistor as the thermal sensor, which replaces the traditional pyroelectric sensors and outperforms thermopiles. The mosaic sensors, which are manufactured by nano-fabrication methods in standard FABs, exhibit enhanced performance and robust manufacturing on wafer level processing and vacuum packaging. Mirror optics instead of Fresnel plastic lenses provides enhanced performance at low-cost. The essential aspects of the design of the mirrors for curtain sensors and presence sensors are presented. The overall measured performance for detecting human targets at extended ranges and hot spots detection are reported. The overall performance of the sensing systems indicate why they are most suitable for consumer electronics, including smart homes, wearables, Internet of Things (IoT) and mobile applications.

This paper presents a sensor and its readout circuit suitable for contact-less temperature measurements. The sensor, designed employing a MEMS technology provided by STMicroelectronics, consists of a miniaturized micromachined silicon thermopile with 180-V/W responsivity, 540- $\text{k}\Omega $ output resistance, and 0.64-mm2 active absorbing area. The interface circuit, fabricated in a standard 130-nm CMOS process, employs chopper technique in order to provide amplification of the sensor output signal, which behaves substantially as a DC while minimizing offset and noise contributions at low frequency. Given the sensor characteristics, a single-ended architecture was preferred over the most straightforward fully-differential approach. The interface circuit reduces the offset by a factor 255, achieving an input referred offset standard deviation equal to 1.365 $\mu \text{V}$ , measured across 29 samples. The thermopile sensor and the interface circuit, integrated in two separate test-chips, were characterized and extensively measured both as stand-alone devices and together as a system to perform contact-less temperature measurements. Adding a metal cap to the thermopile sensor in order to reduce the environmental noise, a measurement accuracy of approximately ±0.2 °C was obtained, thus verifying the system suitability for human body temperature detection.

Integration of unconventional materials on established CMOS platforms requires to fulfill tight thermal budget constraints. However, low temperature processing may result in poor mechanical properties of the deposited films, which can exhibit stress-induced degradation of the optical properties or even delamination. This work focuses on a CMOS-compatible low-temperature deposition process for ZnS films on silicon and its use for the realization of an antireflection coating (ARC) operating in the medium infrared (MIR)–longwave infrared (LWIR) range. A thin interlayer of Al2O3 is employed to achieve good adhesion of a ZnS film deposited on Si by e-beam evaporation at room temperature. Numerical simulations are carried out to optimize the performance of single- and double-side ARC structures, quantifying the impact of the Al2O3 interlayer and of the fabrication tolerances on the optical transmission. Experimental results on an 8” silicon wafer demonstrate a peak transmittance of 66% for single-side ARC and 89% for a double-side ARC at a wavelength of 10 µm, resulting in an average transmission of 76.2% for black body radiation at 36 °C in the 6–20 μm wavelength range.

Thermal IR sensors are widely used in various fields such as automotive, IoT applications, human intruder alert systems as well as smart building management (lighting, heating) or temperature sensing, with an increasing market forecast for the next years. Technologies currently in use for optical uncooled infrared devices are bolometers, thermopiles, and pyroelectric sensors. More recently, a new generation of uncooled thermal sensor based on CMOS-SOI-MEMS technology has emerged, dubbed “TMOS”. The TMOS is a suspended, thermally isolated micro-machined floating transistor, which absorbs infrared radiation. The resulting temperature change is transduced into an electric signal. The TMOS operates in the subthreshold region, therefore requiring low power consumption, which is essential for wearable applications. Moreover, the inherent gain of the transistor results in the highest temperature sensitivity, compared to the commercial thermal sensors. Wafer Level Packaging with a controlled vacuum quality is essential to ensure high performance and low cost. This paper focuses on the study of the thermal performance of a wafer-level packaged TMOS, where the pressure varies between deep high vacuum (0.01 Pa) and atmospheric pressure. The study is based on Finite Element Analysis (FEA) simulations performed by ANSYS software as well as analytical expressions. The measurements of vacuum quality in packaged devices are in line with the modeling and simulations. The talk will describe the TMOS Wafer Level Packaging as well as the modeling and simulations and how to perform vacuum quality measurements of the packaged MEMS device. The talk will present the innovations and the maturity of the new generation of sensors, which are highly useful for wearable and consumer sensor applications.

In this paper, we report on the simulation, design, fabrication and characterization of a tungsten (W) hot plate with a high electro-thermal stability and thermal uniform distribution. The device is constituted by a tungsten multi-rings resistor embedded in a dielectric membrane. Different layouts have been simulated, drawn and tested in order to evaluate and optimize the uniformity of the hot region and the power consumption. For the optimized device the diameter of the hot plate region is 1.25 mm, instead the membrane diameter is 1.83 mm. An innovative layout has been drawn to monitor the temperature uniformity of the hot region: distributed contacts have been integrated on it to be used as sense terminals and to extrapolate the single ring temperature. The same W resistor branches are used as thermal sensors by evaluating in advance the TCR (Temperature Coefficient of Resistance) and extrapolating the temperature by the resistance change. Thermal mapping shows that the temperature uniformity over the heated area is lower than 6% at 400 °C with a power consumption of only 135 mW. Thermal treatments have been performed in order to enhance the device thermal and electrical performances repeatability on wafer.

In this paper, we investigated the applicative using of thermal-magnetic biosensor (TMAGS) for DNA detection. TMAGS is a planar device composed by a primary microcoil able to generate a magnetic field which induces a voltage equal and opposite on two secondary coils. The presence of magnetic material on one of the two secondary coils causes a variation of induced magnetic field especially in the area where the magnetic material is located. In particular, here, we studied the compatibility of two different typologies of beads (MNB1 and MNB2) as magnetic labels towards DNA hybridization process in TMAGS device. These two types of beads differ in size (1 and 0.1 μm), magnetic material location (core or shell), and chemical surface proprieties (electrostatic or covalent bonds possible). In particular, in the first part of the work, we investigate the response of the TMAGS architectures versus the two-bead topology and we found MNB1 exhibits a better output voltage signal (on average 30% higher than the voltage signal of MNB2). On the contrary, when they are employed as magnetic label in a real DNA hybridization process in TMAGS device, only MNB2 typology gives positive results. We ascertain that both the size of the bead and the nature of the chemical bond between the magnetic label (beads) and the DNA target, that must be a covalent bond, play a key role on the success of hybridization reaction. Therefore, a compromise between magnetic content (bead size) and nature of bead-target chemical bond must be selected for the future employment of these devices in molecular detection.

Biosensors are prominent in several areas, such as medical diagnosis, food preparation, pharmaceutical industries, and clinical analysis; high performances are required in spite of attaining accuracy, sensitivity, low cost, easy handling, and portability, but the major parameter that is always representing a challenge for biosensors is specificity. High sensitivity and specificity can be obtained by combining appropriate transduction methods together with immunoassay techniques. In this paper, integrated inductive biosensors for the magnetic immunoassay process, which use magnetic beads as markers for biomolecules, are presented with potential applications to proteins and DNA measurements. The working principle and a dedicated fabrication technology, which also embeds thermal actuation and control, are described; in particular, an improved sensing architecture is proposed here, which allows one to expand the microsensor operative field toward very low bead concentrations. The sensor characterization results are presented together with the analytical model of the transduction principle; a detection limit of approximately 300 beads has been demonstrated. The microsensor is also capable of operating by measuring up to 450 000 beads with a good linearity. Therefore, the sensor architecture proposed here has been demonstrated for wide operating field with high resolution and good linearity; the results proposed confirm the suitability of the devices developed for magnetic immunoassay applications.

This paper presents a readout circuit for thermopile-based thermal sensors, suitable for contactless temperature measurements. The circuit, designed and extensively simulated in a standard 130-nm CMOS process, employs chopper stabilization in order to minimize offset and noise contributions at low frequency, while providing proper amplification to the input signal, which behaves substantially as a DC. The circuit nominal supply voltage is 1.2 V and its power consumption is approximately 260 μW. The proposed single-ended architecture solves the drawbacks of the most straightforward fully differential approach, while achieving a simulated input-referred residual offset mean value equal to 84.4 nV, with 487 nV of standard deviation. An accuracy of ±0.3°C is provided at room temperature, making the circuit suitable for medical devices, such as contactless fever thermometers, and security systems, such as motion and human presence detection sensors.

The miniaturization of microfluidic systems able to manage small sample volumes is one of the key factors for the sensor applications. In this paper, we describe a miniaturized Lab-on-Chip (LoC) system able to electro-loading small volumes of genetic sample (200 nl) via ElectroWetting on Dielectric (EWoD) actuation and detect DNA via polymerase chain reaction (PCR). The core of the system is a miniaturized silicon-based chip that electrically delivers a total volume of 20 μl of liquid into 96 miniaturized chambers of 200 nl each. The chambers are chemically treated with a proper surface process to achieve both a suitable wettability for electro-kinetics liquid loading and surface biocompatibility for PCR process. The chip contains integrated temperature sensors and heaters for driving the PCR thermal process. The system here described is proved to be able to electro-loading small volumes of sample (about 200 nl) and perform PCR amplification in multiple microchambers (up to 96), being a very appealing potential solution for genetic point-of-care applications.

In this paper, a method for the direct quantitative analysis of amplified DNA via q-Polymerase Chain Reaction (qPCR) in miniaturised silicon-based chip system is presented. The designed tool presented here allows the automatic extraction of meaningful information from input fluorescent images by means of digital image processing algorithm. In particular, a smart mathematical model, optimizing the integration of all the analysis steps of the fluorescence data from on chip multiple real time PCR, is described. Such a tool is able to load the digital input images, select and smartly detect the region of interest for fluorescence, elaborate the data input, calculate the average fluorescence values and finally, plot the fitted curve as output, giving also, for each well, both the Cycle Threshold (CT) and Slope parameters. Keywords: Image analysis, qPCR, LabonChip, Edge detection, Hough transform

In this work, we simulated and experimentally assessed the possibility to detect, through electrical transduction, hybridization of DNA molecules on MOS-like devices, having different dielectrics: SiO 2 , Si 3 N 4 and SiO 2 /Si 3 N 4 /SiO 2 (ONO). The electrical characterization was performed after the various functionalization steps, consisting of dielectric activation, silanization, DNA spotting and anchoring, and after the hybridization process, to test the devices effectiveness as DNA recognition biosensors. The experimental results were used to validate device simulations. The comparison shows the ability to determine a priori the DNA probe density needed to maximize the response. The results confirm that the structures analyzed are sensitive to the immobilization of DNA and its hybridization.

We developed a novel silicon biosensor based on magnetoelectronic transduction (MAGS) for nucleic acid detection. The mags-biosensor is a planar device composed by a primary micro-coil, and two secondary coils which produce a differential voltage due to the induced magnetic field. The presence of magnetic material over one of the secondary coils causes variations of induced magnetic field density that in turn results in a total output voltage different from zero. The voltage variation, therefore, is a measure of the amount of magnetic material present in the active zone. A device sensitivity of 5.1 mV/ng and a resolution of 0.008 ng have been observed. The biosensor also presents a micro-heater and a thermal sensor respectively to set and read-out the chip temperature: this aspect enables the device to be used for several biochemical applications that need temperature control and activation such for example nucleic acid amplification (real-time PCR), antigen- antibody detection (immune-assay) and SNP detection. Keywords: Magnetic transduction, Nucleic acid amplification, Micro-heater, Temperature control

In this paper we describe a novel portable system for nucleic acids electrochemical detection. The core of the system is a miniaturized silicon chip composed by planar microelectrodes. The chip is embedded on PCB board for the electrical driving and reading. The counter, reference and work microelectrodes are manufactured using the VLSI technology, the material is gold for reference and counter electrodes and platinum for working electrode. The device contains also a resistor to control and measuring the temperature for PCR thermal cycling. The reaction chamber has a total volume of 20 μL. It is made in hybrid silicon–plastic technology. Each device contains four independent electrochemical cells.Results show HBV Hepatitis-B virus detection using an unspecific DNA intercalating redox probe based on metal–organic compounds. The recognition event is sensitively detected by square wave voltammetry monitoring the redox signals of the intercalator that strongly binds to the double-stranded DNA. Two approaches were here evaluated: (a) intercalation of electrochemical unspecific probe on ds-DNA on homogeneous solution (homogeneous phase); (b) grafting of DNA probes on electrode surface (solid phase).The system and the method here reported offer better advantages in term of analytical performances compared to the standard commercial optical-based real-time PCR systems, with the additional incomes of being potentially cheaper and easier to integrate in a miniaturized device. Keywords: Electrochemical detection, Real time PCR, Unspecific DNA intercalator

We report on the fabrication and performance of Si-based light sources. The devices consist of MOS structures with erbium (Er)-doped silicon rich oxide (SRO) film as gate dielectric. The devices exhibit electroluminescence (EL) at 1.54 μm at room temperature with a 0.2% external quantum efficiency. These devices show a high stability due to the silicon excess in the film. The Er-doped SRO films have been introduced in a Si/SiO 2 Fabry–Perot Microcavity in order to increase the spontaneous emission rate, the extraction efficiency and the spectral purity at the resonant wavelength. The active medium in the cavity has been electrically pumped and the conduction mechanisms have been analyzed. The EL spectra have also been acquired and compared with photoluminescence (PL) ones for the same resonant cavity light-emitting device (RCLED). The EL and PL peak intensities of the on-axis emission at the resonant wavelength are over 20 times above that of the similar Er-doped SRO film without a cavity. The Si-based RCLEDs exhibit different quality factors, ranging from 60 to 170. The spectra shape and intensity have been correlated with the quality factor. A high directionality of the emitted light, due to the presence of the resonant cavity, has also been observed: the overall luminescence is confined within 10° cone from the sample normal.

We report on the fabrication and performances of highly efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. They exhibit strong 1.54 μm electro-luminescence (EL) at 300 K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III–V semiconductors. Emission at different wavelengths has been achieved incorporating different rare earths (terbium (Tb) and ytterbium (Yb)) in the gate dielectric. The external quantum efficiency depends on the rare-earth ions incorporated and ranges from 10% (for a Tb doped MOS) to 0.1% (for an Yb doped MOS). RE excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped silicon rich oxide (SRO) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 0.2%. In these devices, Er pumping occurs partially by hot electrons and partially by energy transfer from the Si nanostructures to the rare-earth ions, depending on Si excess in the film. Si/SiO 2 Fabry–Perot microcavities have been fabricated to enhance the external quantum emission along the cavity axis and the spectral purity of emission from the films that are used as active media to fabricate a Si-based resonant cavity light emitting diode (RCLED). These structures are fabricated by chemical vapour deposition on a silicon substrate. The microcavities are tuned at different wavelengths (nm): 540, 980 and 1540 (characteristic emission wavelengths, respectively, for Tb, Yb and Er). The reflectivity of the microcavities is about 97% and the quality factor ranges from 60 (for the cavity tuned at 980 nm) to 95 (for the cavities tuned at 540 and 1540 nm).

We report on the fabrication and performances of extremely efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 μm electroluminescence (EL) at 300 K with a 10% external quantum efficiency, comparable to that of standard light-emitting diodes using III–V semiconductors. Er excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light-emitting MOS devices have been fabricated using Er-doped silicon rich oxide (SRO) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 1%. In these devices, Er pumping occurs by energy transfer from the Si nanostructures to the rare-earth ions. Finally, we have also fabricated MOS structures with Tb- and Yb-doped SiO2 which show room temperature EL at 540 nm (Tb) and 980 nm (Yb) with an external quantum efficiency of a 10% and 0.1%, respectively.

We report on the fabrication and performances of highly efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1540 nm electroluminescence at 300K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III-V semiconductors. Emission at different wavelenghts has been achieved incorporating different rare earths (Ce, Tb, Yb, Pr) in the gate dielectric. RE excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped SRO (Silicon Rich Oxide) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 0.2%. In these devices different pumping mechanisms for the Er ions are simultaneously operating: Er can be excited by direct hot electron impact (like in stoichiometric oxide MOS) and by energy transfer from excited Si nanostructures, depending on the Si excess in the film. We propose a model to describe the electrical conduction mechanism in a Silicon Rich Oxide film. The electrical characteiristics can be fitted by a Schottky emission mechanism at low electrical fields and by a SCLC(Space Charge Limited Conduction) model for high elctrical fields. Data obtained from C-V measurements confirm the proposed model.

We report on the fabrication and characterization of Si/SiO 2 Fabry-Perot microcavities. These structure are used to enhance the external quantum emission along the cavity axis and the spectral purity of emission from Rare earth doped and undoped SiOx (x ≤ 2) films that are used as active media to fabricate a Si based RCLED (Resonant Cavity Light emitting Devices). These structures are fabricated by chemical vapour deposition on a silicon substrate. The microcavities are tuned at different wavelengths: 540 nm, 980 nm, 1540 nm, 780 nm and 850 nm (characteristic emission wavelength respectively for Tb, Yb and Er and Silicon Rich Oxide (SRO)). The reflectivity of the microcavities is of 97% and the quality factor ranges from 50 (for the cavity tuned at 540nm) to 95 (for the cavities tuned at 980 nm and 1540 nm) and 150 (for the cavity tuned at 780 nm and 850 nm). These cavities have been characterized by TEM analysis to evaluate film uniformity, thickness and densification after annealing process for temperature ranging from 800° to 1100°C. The reflectivity and photoluminescence spectra show resonant wavelengths in agreement with the calculated values. A new structure to electrically pump the active media has been designed. The electrical properties of the active media have been analysed. An enhancement of the photoluminescence signal of twenty times have been achieved for the selected emission wavelength.

We report on the fabrication and performances of the most efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 μm electroluminescence at 300K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III-V semiconductors. Emission at different wavelenghts has been achieved incorporating different rare earths (Ce, Tb, Yb, Pr) in the gate dielectric. The external quantum efficiency depends on the rare earth ions incorporated and ranges from 10% (for an Tb doped MOS) to 0.1% (for an Yb doped MOS). RE excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped SRO (Silicon Rich Oxide) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 0.2%. In these devices Er pumping occurs part by hot electrons and part by energy transfer from the Si nanostructures to the rare earth ions, depending by Si excess in the film. Si/SiO2 Fabry-Perot microcavities have been fabricated to enhance the external quantum emission along the cavity axis and the spectral purity of emission from the films that are used as active media to realize a Si based RCLED (resonant cavity light emitting diode). These structures are realized by chemical vapour deposition on a silicon substrate. The microcavities are tuned at different wavelengths: 540nm, 980nm and 1540nm (characteristic emission wavelengths respectively for Tb, Yb and Er). The reflectivity of the microcavities is of 97% and the quality factor ranges from 60 (for the cavity tuned at 980nm) to 95 (for the cavities tuned at 540nm and 1540nm).

We report on the fabrication and performances of the most efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 µm electroluminescence at 300K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III-V semiconductors. Er excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped SRO (Silicon Rich Oxide) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 1%. In these devices Er pumping occurs by energy transfer from the Si nanostructures to the rare earth ions.

We investigated the properties of light emitting devices whose active layer consists of Er-doped Si nanoclusters (nc) generated by thermal annealing of Er-doped SiOx layers prepared by magnetron cosputtering. Differently from a widely used technique such as plasma enhanced chemical vapor deposition, sputtering allows to synthesize Er-doped Si nc embedded in an almost stoichiometric oxide matrix, so as to deeply influence the electroluminescence properties of the devices. Relevant results include the need for an unexpected low Si excess for optimizing the device efficiency and, above all, the strong reduction of the influence of Auger de-excitation, which represents the main nonradiative path which limits the performances of such devices and their application in silicon nanophotonics.