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This is the fourth part of a study presenting a miniature, combustion-type gas sensor (dubbed GMOS) based on a novel thermal sensor (dubbed TMOS). The TMOS is a micromachined CMOS-SOI transistor, which acts as the sensing element and is integrated with a catalytic reaction plate, where ignition of the gas takes place. The GMOS measures the temperature change due to a combustion exothermic reaction. The controlling parameters of the sensor are the ignition temperature applied to the catalytic layer and the increased temperature of the hotplate due to the released power of the combustion reaction. The solid-state device applies electrical parameters, which are related to the thermal parameters. The heating is applied by Joule heating with a resistor underneath the catalytic layer while the signal is monitored by the change in voltage of the TMOS sensor. Voltage, like temperature, is an intensive parameter, and one always measures changes in such parameters relative to a reference point. The reference point for both parameters (temperature and voltage) is the blind sensor, without any catalytic layer and hence where no reaction takes place. The present paper focuses on the study of the effect of humidity upon performance. In real life, the sensors are exposed to environmental parameters, where humidity plays a significant role. Humidity is high in storage rooms of fruits and vegetables, in refrigerators, in silos, in fields as well as in homes and cars. This study is significant and innovative since it extends our understanding of the performance of the GMOS, as well as pellistor sensors in general, in the presence of humidity. The three main challenges in simulating the performance are (i) how to define the operating temperature based on the input parameters of the heater voltage in the presence of humidity; (ii) how to measure the dynamics of the temperature increase during cyclic operation at a given duty cycle; and (iii) how to model the correlation between the operating temperature and the sensing response in the presence of humidity. Due to the complexity of the 3D analysis of packaged GMOS, and the many aspects of humidity simultanoesuly affecting performane, advanced simulation software is applied, incorporating computational fluid dynamics (CFD). The simulation and experimental data of this study show that the GMOS sensor can operate in the presence of high humidity. [ABSTRACT FROM AUTHOR]

The electrooptical characterization of three groups of CMOS image sensors with front-side illumination based on the different technologies namely CMOS 0.35 [mu]m-technology, novel CMOS/SOI 0.35 [mu]m-technology and CMOS 0.5 [mu]m-technology is reported. It is found that there is strong dependence of quantum efficiency of the photodiodes on the architecture of the image sensor which are useful for designing and modeling CMOS/SOI image sensors.

The characterization of the achievable high temperature coefficient of current (TCC) of standard CMOS transistors implemented in silicon-on-insulator (SOI) substrates is discussed. Achievable TCC of more than 6 percent K in subthreshold and less than -0.4 percent/K in saturation is observed.

Magnetostatic actuators exhibit bistability similarly to the Pull-In phenomena of electrostatic actuators. In this paper a methodology and model for the extraction of the magnetic Pull-In parameters of magnetostatic actuators are derived. The flux-controlled magnetostatic actuator is analyzed based on the energy representation and the magnetomotive force-controlled magnetostatic actuator is analyzed in the thermodynamic potential energy (or co-energy) representation. An algebraic equation, referred to as the magnetic Pull-In equation, for each of the two cases (flux-controlled and magnetomotive force-controlled actuators) is derived. By solving these Pull-In equations either analytically or numerically, the magnetic Pull-In parameters are obtained. Several case studies, covering displacement and torsion magnetic actuators, are presented and analyzed, illustrating the usefulness of the proposed methodology, its relative simplicity as well as the adaptability and practical usage in wide spectrum of magnetic actuators. Index Terms--Actuators, magnetic, magnetostatic, model, pull-in.

In this work, an experimental and theoretical study of the effect of various geometrical parameters on the electromechanical response and pull-in parameters of torsion actuators is presented. A lumped two-degrees-of-freedom (L2DOF) pull-in model that takes into account the bending/torsion coupling, previously proposed for cantilever suspended actuators, is tailored for the torsion actuators under study. This model is shown to better capture the measured pull-in parameters than previously proposed lumped single-degree-of-freedom (L1DOF) models. The measurements were conducted on torsion actuators with various shapes, fabricated on silicon-on-insulator (SOI) wafers using deep reactive ion etching (DRIE) and flip-chip bonding. Furthermore, a novel rapid solver, for extracting the pull-in parameters of the L2DOF model of the torsion actuators, is proposed. The proposed solver is based on a Newton-Raphson scheme and the recently presented DIPIE algorithm and is shown to be ~10 times faster than the prevalent voltage iterations based solvers. The rapid and more accurate pull-in extraction of the proposed approach renders it as a tool for extensive analysis and design optimization of torsion actuators. [951] Index Terms--Actuator, experimental, lumped two-degrees-of-freedom (L2DOF), model, pull-in, torsion.

This work presents a systematic analysis of electrostatic actuators driven by multiple uncoupled voltage sources. The use of multiple uncoupled voltage sources has the potential of enriching the electromechanical response of electrostatically actuated deformable elements. This in turn may enable novel MEMS devices with improved and even new capabilities. It is therefore important to develop methods for analyzing this class of actuators. Pull-in is an inherent instability phenomenon that emanates from the nonlinear nature of the electromechanical coupling in electrostatic actuators. The character of pull-in in actuators with multiple uncoupled voltage sources is studied, and new insights regarding pull-in are presented. An analytical method for extracting the pull-in hyper-surface by directly solving the voltage-free K-N pull-in equations derived here, is proposed. Solving simple but interesting example problems illustrate these new insights. In addition, by using current methods. [898] Index Terms--Electrostatic actuator, multiple voltage sources, pull-in.

Pull-in parameters are important properties of electrostatic actuators. Efficient and accurate analysis tools that can capture these parameters for different design geometries, are therefore essential. Current simulation tools approach the Pull-In state by iteratively adjusting the voltage applied across the actuator electrodes. The convergence rate of this scheme gradually deteriorates as the Pull-In state is approached. Moreover, the convergence is inconsistent and requires many mesh and accuracy refinements to assure reliable predictions. As a result, the design procedure of electrostatically actuated MEMS devices can be time-consuming. In this paper a novel displacement iteration Pull-In extraction (DIPIE) scheme is presented. The DIPIE scheme is shown to converge consistently and far more rapidly than the voltage iterations (VI) scheme (> 100 times faster!). The DIPIE scheme requires separate mechanical and electrostatic field solvers. Therefore, it can be easily implemented in existing MOEMS CAD packages. Moreover, using the DIPIE scheme, the Pull-In parameters extraction can be performed in a fully automated mode, and no user input for search bounds is required. [782] Index Terms--Actuator, computer-aided design (CAD), displacement iteration Pull-In extraction (DIPIE), electrostatic, Pull-In.

An important design issue of electrostatic torsion actuator is the relative locations of the actuating electrodes, where the bias voltage is applied. These geometrical design parameters affect both the Pull-In angle as well as the Pull-In voltage. In this paper, a new approximated analytical solution for the Pull-In equation of an electrostatic torsion actuator with rectangular plates is derived. The analytical expression is shown to be within 0.1% of the one degree of freedom (1DOF) lumped-element model numerical simulations. Moreover, the analytical expressions are compared with the full coupled-domain finite-elements/boundary-elements (FEM/BEM) simulations provided by MEMCAD4.8 Co-solve tool, showing excellent agreement. The approach presented here provides better physical insight, more rapid simulations and an improved design optimization tool for the actuator. [661] Index Terms--Actuator, design, electrostatic, pull-in, torsion.

This paper presents a generalized model for the pull-in phenomenon in electrostatic actuators with a single input, either charge or voltage. The pull-in phenomenon of a general electrostatic actuator with a single input is represented by an algebraic equation referred to as the pull-in equation. This equation directly yields the pull-in parameters, namely, the pull-in voltage or pull-in charge and the pull-in displacement. The model presented here permits the analysis of a wide range of cases, including nonlinear mechanical effects as well as various nonlinear, nonideal, and parasitic electrical effects. In some of the cases, an analytic solution is derived, which provides physical insight into how the pull-in parameters depend upon the design and properties of the actuator. The pull-in equation can also yield rapid numerical solutions, allowing interactive and optimal design. The model is then utilized to analyze analytically the case of a Duffing spring, previously analyzed numerically by Hung and Senturia, and captures the variations of the pull-in parameters in the continuum between a perfectly linear spring and a cubic spring. Several other case studies are described and analyzed using the pull-in equation, including parallel-plate and tilted-plate (torsion) actuators taking into account the fringing field capacitance, feedback and parasitic capacitance, trapped charges, an external force, and large displacements. [655] Index Terms--Actuators, electrostatic, MEMS, model, pull-in.

The 1/f noise in CMOS transistors was measured at room temperature on transistors with varying gate area.

Pull-in study of an electrostatic microactuator is essential for making the electrostatic actuation more effective. In this paper, pull-in analysis is presented for an electrostatic torsion microactuator. The torsion microactuator can be used as a microtorsion mirror. A polynomial algebraic equation for the pull-in voltage and pull-in angle of a torsion microactuator is derived. Two types of microactuators fabricated using bulk micromachining are presented. Measurements done on the fabricated microactuators are reported, showing deviations within 1% error from the calculations. [325] Index Terms - Electrostatic, microactuator, micromirror, pull-in, torsion.

A novel design of a micromachined vibrating rate gyroscope is presented. The rate gyroscope consists of a suspended proof mass which is attached by indium bumps to a CMOS chip. The proof mass is excited to vibration by electrostatic force. The displacements due to rate are sensed optically, using CMOS-integrated photodiodes and analog electronics. System considerations, including the mechanical behavior, optical sensing, electronics, and noise sources of the rate gyroscope, are discussed. An expression for the noise equivalent rate (NER) of the system is obtained in order to derive an optimal design approach for the rate gyroscope. Optimal design and simulations of a case study of a rate gyroscope are presented. The device shows the ability of sensing 1 deg/h even at moderate quality factors of the order of 5000 and low-excitation voltages of 2.25 V. Index Terms - Gyroscope, MEMOS, MIDOS, noise, optical, rate.

CdTe and CdZnTe X-ray detector arrays for imaging and spectroscopy provide low capacitance current sources with low leakage currents. The optimal shaping time for low-noise operation is relatively high in CMOS analog channels that provide the readout for these detectors. The shaper is centered at lower frequencies, and thus the 1/f noise from the electronics is the main noise source that limits the resolution of the channel. The optimal dimensions of the input stage MOSFET are determined by this noise. In this paper a design criterion for the optimization of the resolution and the power consumption in a 1/f noise dominated readout is introduced. A readout based on CMOS switched charge sensitive preamplifier without feedback resistor has been designed and fabricated in the CMOS 2-[microns] low-noise analog process provided by MOSIS. This design provides high sensitivity and the possibility to integrate a large number of channels with low power consumption. Measurements of the performance of a first prototype chip are presented. Index Terms - CdTe, CdZnTe, charge sensitive preamplifiers, CMOS amplifiers, low-noise amplifiers, X-ray detectors.

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. [ABSTRACT FROM AUTHOR]

A surface passivation method suitable for an array of backside-illuminated indium antimonide photovoltaic diodes is presented. It consists of a chemical pretreatment followed by photo-assisted SiOx deposition to tailor the characteristics of the semiconductor-passivating interface and the passivating layers. A process description is given together with the results of the indium face that detects the photons and the antimony face that contains the implanted junctions.

A mathematical model for the thermal noise of long-channel buried-channel metal oxide semiconductor transistors is proposed. It obtains the thermal noise behavior as a function of both device fabrication parameters and the four terminal voltages. The model, which is based on charge-voltage expressions, facilitated the derivation of analytical noise models valid for all operating states. Its validity is confirmed by the good fit between experimental results and model simulation.

The measurement of the bulk lifetime of etch-thinned InSb wafers is studied. Such a wafer that has undergone the processing required for infrared focal plane array applications is also presented. The wafer was developed for the direct quantification of the diffusion length, the parameter providing the bulk lifetime. Results indicate the insensitivity of the semiconductor to the fabrication process that consists of etch-thinning, passivation and lithography.