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After a theoretical and analytical study of the body effect in MOS transistors, this paper offers two useful models of this parasitic phenomenon. Thanks to these models, a design methodology, which takes advantage of the bulk terminal, allows to turn this well-known body-effect drawback into an analog advantage, giving thus an efficient alternative to overcome the design constraints of the CMOS VLSI wireless mass market. To illustrate the approach, four RF building blocks are presented. First, a 0.9V 10dB gain LNA, covering a frequency range 1.8-2.4GHz, thanks to a body-effect common mode feedback, is detailed. Secondly, a body-effect linearity controlled pre-power amplifier is presented exhibiting a 5dBm input compression point (ICP1) variation under 1.8V power supply for half the current consumption. Lastly, two mixers based on body-effect mixing are presented, which achieve a 10dB conversion gain under 1.4V for a -52dB LO-to-RF isolation. Well suited for low-power/low-voltage applications, these circuits implemented in a 0.18@mm CMOS VLSI technology are dedicated to multi-standard architectures and system-on-chip implementations.

This paper presents an original method of analog circuits aging simulation. This method is based on a behavioral modelling of circuits that includes the effects of degradations on circuit parameters, on the basis of transistors aging. The efficiency of the method is demonstrated in the case of hot carriers degradation in an amplifier

When printed circuit boards (PCBs) are exposed to humid ambient conditions an absorption of moisture will occur. This infects the reliability of the PCB and also delamination can occur during reflow. Copper layers in the PCB act as diffusion barrier and have an influence of the moisture distribution and out of this an influence on the moisture concentration in the PCB. Depending on the location the time to get dry PCB increases. In this paper the measurement of different PCB samples will be compared with concentration distribution out of simulations.

Automotive requirements are nowadays not only limited to high temperatures but more and more demands are driven towards vibration and higher acceleration values due to the direct mounting of the Electronic Control Units on the Engine. Temperature cycle testing and combined testing methods have been under study for a long time but literature concerning Vibration Modelling is very poor in comparison with thermal models like Arrhenius or thermo-mechanical based models like Coffin-Manson. In this article, a revisit of the Steinberg Model is presented with a direct application on tantalum capacitors populated boards. Experimental results with various sinusoidal excitation g-level are presented; whereas on the other side FEM simulations are performed and results are implemented in the Steinberg Model, in order to identify model parameters.

By measuring shifts in the resonant frequency of a silicon microcantilever coated with a sensitive layer, it is possible to obtain a competitive chemical microsensor. In fact, the sensitivity of such a microsensor is improved when used in high resonant frequency device. Usually, to increase the resonant frequency, smaller microcantilevers are used. The limitation on increasing the natural frequency by reducing the microstructure size is often due to the limitation of the deflection measurement principle. Furthermore, it could also be difficult to obtain reproducible sensitive coatings on very small surfaces. In order to achieve high sensitivities corresponding to high frequencies without decreasing the microstructure size, high-order flexural modes can be considered. In this paper, it is demonstrated that the theoretical performance of the resonant microcantilever chemical sensor is essentially due to the resonant frequency value and not due to the mode order. The advantages of increasing the resonant frequency by using high-order modes is also confirmed experimentally.

Standard screen-printing is a very versatile technology for the elaboration of thick films and hybrid circuits. However, in order to obtain components with particular properties such as gas sensors, varistors, PZT-based pyroelectric sensors, super-thick copper pads, etc., a better control of the layer compacity is necessary. This has been made possible, thanks to the preparation of specific inks and thanks to the development of new fabrication processes. Most examples will be drawn from our own experience.

For the millimetric wave transport over fiber, one of the most simple ways to eliminate the periodic fading due to chromatic dispersion is to use an optical Single Side Band signal. In accordance with this principle, this paper presents highly linear millimetric amplifiers driving a SSB modulator. For the first time, the real-frequency technique has been successfully applied to the design of the matching networks of 26.5–29.5 GHz and 40.9–41.8 GHz amplifiers.

Silicon microcantilevers can be used as microbalances or chemical microsensors if a sensitive layer is deposited on the moving structures. Indeed, the sorption of specific species by the sensitive coating modifies the mechanical properties of the structure and then its fundamental natural frequency. In this paper, analytical expressions of the sensitivities of different structures are obtained in view of optimization of the geometrical parameters for both mass sensors or concentration gas sensors. For chemical sensors, a thin parallelepiped microcantilever with sensitive coating on the whole structure gives good performances especially regarding the sensibility. However, the frequency measurement and the active surface can be improved with a rectangular plate at the free-end of the microcantilever with little influence on the sensitivities.

A fast response humidity sensor was fabricated to equip a medical microsystem for diagnosis of pulmonary diseases. Its main characteristics are reported in this paper. The sensor is based on a capacitor made of a divinyl siloxane benzocyclobutene (BCB) thin film in between parallel plate electrodes. It was fabricated with compatible CMOS technology. It exhibits good linearity, good sensitivity, and a short response time. Equilibrium capacitance variations versus humidity can be considered linear with a linearity error less than 2% of the humidity level. The sensitivity is 0.1 pF by per cent of the humidity level. The device displays a typical adsorption time of 650 ms, a minimum adsorption time of 400 ms, and a desorption time of a few seconds at ambient temperature. Its performances were compared to other types of capacitive humidity sensors fabricated for the same medical use. The static behavior and the dynamic behavior of the device are reported. They are interpreted according to physical processes of gas adsorption and diffusion in and through glassy polymers. The suitability of the conventional Dual-Mode model to explain water sorption in BCB is discussed. This investigation is a starting point in a modeling process to improve the design of the sensor interface circuitry.

In this paper, the RBS phenomenon is described and experimental results concerning Bragg reflectors and microcavities grown on silicon substrates by molecular beam epitaxy are presented. This spectroscopy is not sensitive to (i) the lateral fluctuation of the alloy composition (the analyzed surface is about 1 mm(2)), (ii) to the residual strain of the layer or to (iii) the internal electric field. The measured thicknesses and compositions of the layers are very close to the nominal values. The Al concentration have been confirmed by low temperature photoluminescence experiments and the thicknesses by scanning electron microscopy studies. The straggling effect has been highlighted and plotted as function of the penetration depth of the particles.

Within the framework of specific applications, electronic components and systems are submitted to more and more serious environmental stresses. Industrial applications such as automotive or geothermal researches push back the limits of stress threshold that boarded electronic circuits can tolerate. We will expose here a study involving both thermal stress conditions and isostatic pressure from 0.1 to 120 MPa applied to MCM-L technology. Particular attention was given to the behavior of passive components under pressure stress. The relative variation of electrical response in ceramic capacitors and SMD resistors under pressure has clearly been demonstrated. The other aim of this study was to characterize the sensitiveness of usual coating resins under hydraulic oil medium under pressure. One of the results of this study was to demonstrate a relative immunity to hydraulic oil penetration during life test of about 1000 h under 120 MPa.

This work describes the implementation of an experimental procedure to evaluate the reliability of Heterojunction Bipolar Transistors (HBT) on a GaAs substrate. It is based on the separation of aging test accelerating factors applied on two test vehicles: HBT and Transmission Line Model (TLM) structures associated with emitter, base and collector layers. To identify the physical origin of the degradation mechanism, analysis techniques are used: EDX, SEM and TEM observations for which a new sample preparation method has been worked out. Three different technological fabrication processes, are investigated: AlGaAs/GaAs double-mesa HBT, GaInP/GaAs self-aligned HBT and GaInP/GaAs fully planar HBT. These investigations have revealed two major failure mechanisms: the degradation of SiN–GaAs interface correlated with the increase of emitter-to-base leakage current of HBT submitted to combined bias and temperature stresses; the detachment of Ge/Mo/W emitter ohmic contact related to the base and collector current decrease for high level injection in forward regime. A 2D simulation has lead to modify the interface electrical properties to evaluate the impact of the two degradations on HBT dc characteristics.

The reliability of ion-implanted power MESFETs submitted to RF and DC life-tests in impact ionization regime has been investigated by DC electrical characterization, LF noise analysis and Drain Current Transient analysis (DCTS). The two types of life-test have induced no degradation of the channel. RF life-test has induced DC parameter evolutions, but no significant drift of dynamic performances. Different evolutions of the interface state effective density in the gate-drain access region have been induced after DC and RF life-test.

Electrical characterizations of different compositions of the fluorite-type Ca 1− x Er x F 2+ x (0≤ x ≤0.38) solid solution on the form of sintered pellets and thin films have allowed to evaluate the influence of the morphology on the electrical properties. Results obtained are discussed and correlated to growth rate of clustering process which is developing when x increases.

A surface acoustic wave (SAW) organophosphorus gas detector has been designed, fabricated and tested. The gas detector consists of a dual delay line fabricated on a single quartz substrate. Each delay line is connected into the feedback path of a radio-frequency amplifier, to realize a SAW oscillator. The propagation path of one delay line is coated with fluoropolyol (FPOL). These polymers offer an interesting way to detect organophosphorus compounds like GB at low concentration levels. The absorption of vapors induces phase variations due to mass loading and stress effects. These variations result in corresponding frequency shifts. In this work, we have synthesised the four FPOL isomer combinations separately and characterized these materials by physico–chemical analysis. A series of SAW sensors have been coated with these materials and experimental results as a function of vapor concentration are presented. The influence of coating thickness, temperature and humidity are examined. Results showed on one hand that frequency variations are linear with GB gas concentrations from 0.5 to 10 ppm and on the other hand that sensitivity to organophosphorus compounds is two times greater in wet atmospheres (RH=60%) than in dry air. The sensitivity was also better at a working temperature close to the glass transition point ( T G ) of the polymer. Above T G , the modification of the polymer structure induced a great radiation of the acoustic energy in the coating.

SUMMAKY In this paper we present a comparison between two non-destructive techniques for crack detection in MLCCs. First, if a type II MLCC is biased with a DC field, the capacitor becomes temporarily 'poled' and can act as a transducer. This is induced by a residual piezoelectric effect used in the impedance spectroscopy method. Second, we used a scanning ultrasonic system working in the 10-100 MHz frequency bandwidth. To understand the ultrasonic signature, we used time-of-flight (TOF) detection with short-time Fourier transform (STFT) analysis to determine the depth and nature of defects with high accuracy. An application of digital signal processing to the characterization of defects is presented for a lot of MLCCs with cracks defects. For comparison, the same lot was tested with the piezoelectric method. The two techniques are closely correlated.

The authors present an analytical approach of the line width control in photore- sist sensitized using a laser beam lithography bench. They take into consideration parameters of the photoresist such as the Dill parameters, the absorbance and the reflection factor as well as parameters of the etching process such as the speed and the intensity of the laser beam. They give a large study of the time and spatial dependence of the absorbance during the passage of the laser beam spot on the photoresist surface and present experimental results in accordance with their theoretical approach.

The use of library cells, specially designed for their sensitivity to a laser beam, is a potential solution for both ‘observability’ and ‘controllability’ problems encountered by the test engineers. The basic principle relies on the photo-induced current generated in the laser beam-silicon interaction. The ‘observation’ cells, when probed by the beam, are used to read directly a logic level inside the circuit, whereas the ‘control’ cells are used to force a particular node of the circuit. A test structure including a 16 bits counter with 16 ‘observation’ cells and 1 ‘control’ cell has been fabricated in BiCMOS technology in order to illustrate this new testing method.

The evolution of the 1/f gate noise in GaAs DCFET has been analyzed in the impact ionization regime. As the drain bias Vd is raised, a steep increase of the 1/f gate current noise is observed in correlation with the triggering of the impact ionization mechanism. A novel and empirical model of the 1/f low frequency gate current noise S/sub ig/ measured in the impact ionization regime is proposed. The following relation fits it with an exponential law: S/sub ig/=E exp (-F/Vd) (1/f), which is similar to the well-known dependence of the impact ionization rate /spl alpha/ on the drain bias.

A current-controlled current source and a voltage-controlled voltage source are used in conjunction with four passive components to implement second-order bandpass filters. The circuits, which exhibit reduced values for their active and passive sensitivities, can be used in a very large frequency range when the active elements are designed from high-performance bipolar arrays. Simulated results using SPICE, which confirm the theoretical analysis, are reported and discussed for active elements implemented in a translinear form. Experimental results are given indicating that the implementation compares favorably with conventional ones. >

International audience; We present in this article a dual-standard dual-mode low-noise amplifier (LNA) for DCS1800/W-CDMA-FDD applications. In order to save die area compared to conventional parallel LNAs, we have employed an alternative circuit configuration. It consists of sharing the most die consuming elements (inductances) in both operation standards, enabling a more compact solution. The standard selection is performed through a bias scheme (MOS switches) that allows alternating between the two involved standards. The LNA die area is 1.0 x 1.2 mm² and it consumes 6.8mW (3.8mA under 1.8V), including bias circuitry

The development of complex and high-performance technologies for microelectronic and optoelectronic systems has created a revolution in the main applications during the last ten years. These performances can be reached by packaging interface and control circuits with the optical chips leading to the concept of highly reliable and technically-advanced microsystems which can be used by end-users without the need for a detailed knowledge of technology. Developing low-cost, low-consumption, hermetic and highly efficient microsystems associated with mechanical stability is one of the key issues for such systems. Packaging of these kinds of systems requires the solution of optical, mechanical and electrical problems. These problems are often highly interactive and the stability of devices is an essential factor in ensuring high performances and developing reliable solutions. Based on environmental and functional specifications, the product development can start with a technical risk-analysis phase. This phase aims to point out the major risks for a given product design. These risks are then assessed and lowered through dedicated action plans performed on representative test units or complete products. In this case, physical simulations (thermal, mechanical and thermomechanical) can also be used to give complementary information and to assess the risk criticality, in order to understand the behavior of the system [1].

This paper presents a ladder BAW-SMR filter with improved isolation for application in W-CDMA reception band (2.11 - 2.17 GHz). The high isolation is achieved by placing one transmission zero at the W-CDMA transmission band (1.92 - 1.98 GHz). It could be implemented thanks to a design technique that employs bonding wires to introduce transmission zeros. This technique enables to increase the rejection of ladder BAW filters. The filter presents: 1.6 dB of insertion loss, 16 dB of return loss and isolation higher than 35 dB at TX band (1.92 - 1.98 GHz).

In this paper, we propose an alternative method to characterize the end effects in shorted slotlines. Using a commercial software to model the transition, a simple mathematical expression of the end impedance, valid for a given substrate family and in a wide frequency domain, was achieved. Several dielectric substrates were considered and the obtained results were compared with experimental ones. A correct agreement was observed. This approach can also be useful in more complex simulations relative to multilayer structures.

This paper presents a MATLAB code which simulates the response of capacitive humidity sensors subjected to humidity variations. The sensors have parallel electrodes and dielectric polymer-based sensitive coatings. User-defined parameters regard the geometry of the sensor, the physical chemistry of sorption in the sensitive film and the environment of the sensor. The code includes electrostatic and gas diffusion calculation. The diffusion model is based on the theory of molecule diffusion in polymer films. The confrontation of this code with finite element simulation and experimental results demonstrates its accuracy. Experiments were carried out for DVS-BCB polymer films 1.3, 1.55 and 3.5 /spl mu/m thick with various tipper electrode geometries. Although humidity sensors are dealt with in this paper, the code can be used for the optimization of capacitive sensors for other gases.

The following discussion presents the design and measurements of a power amplifier for a WCDMA handset application on silicon with a STM BiCMOS 0.25mum process. An analysis of the impact of temperature on linearity especially on adjacent channel power regrowth is proposed

The efficiency of a monomolecular film of (3-glycidoxypropyl) trimethoxysilane (GPTS) on a shear horizontal guided (Love) acoustic wave immunosensor to detect whole Escherichia coli ( E. coli ) bacteria is demonstrated. Direct anti- E. coli antibodies grafting onto the sensor surface did not lead to a significant bacteria immobilisation, partially attributed to the SiO 2 sensor surface roughness. An innovative method has been set up to get around this difficulty and to detect whole bacteria. It consists in grafting goat anti-mouse antibodies (GAM) onto the sensor surface in a first step and introducing E. coli bacteria mixed with anti- E. coli antibodies onto the sensor in a second step. We describe the characteristics of such a technique like sample preparation time (lower than 30 min) and temperature improvements. A 37 °C experimental temperature led to the fastest bacteria binding kinetic, reducing the total analysis time. This method enables to keep the specificity of the antibody/antigen interaction and provides significant results in less than 1 h. This leads to a detection threshold of 10 6 bacteria/ml in a 500 μl chamber.

A long-term 3000-hour test under on-state conditions (VDS =25V, 6W/mm constant dissipated power) and off-state conditions (V DS=46V, VGS=-6V) on GaN/AlGaN/GaN HEMTs is presented. Trapping presence and hot-electrons effect are characterized by means of low-frequency techniques (low-frequency noise measurements, transconductance frequency dispersion, gate-lag). The on-state stress shows the most important degradation. Since our measurements point out to the creation of traps in the gate-to-drain surface region during the stress, this degradation is ascribed to the effect of hot-electrons

This paper presents the application of picosecond laser ultrasonics for integrated circuit inspection and failure analysis. The technique is described and illustrated with several results. The potential for metal and inter-metal layers metrology in the context of process characterization is illustrated

We present a broadband, compact and scalable equivalent circuit model for on-chip transformers with patterned ground shield fabricated in silicon IC technology. The model is driven from the layout and process technology specifications. It is suitable for design optimization and circuit simulation. Verification with measurement data from SiGe process demonstrates performance prediction and excellent scalability of the model.

International audience

International audience