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The fabrication process of a microparabolic reflector using isotropic xenon difluoride Xe F 2 etching technique is presented and analysed through this work for developing infrared antenna-coupled detectors. Although many parametric studies described the behaviour of this process in the literature, the non-linearity of the process and its dramatic dependency on the pattern definition result in great difficulties when adopting the process for developing a particular structure. The main focus of this work is, therefore, to present a detailed etching analysis as dictated in the proposed design providing the proper etching recipe according to the proposed structure design and its associated masking pattern. Deep insights into the process have been highlighted suggesting the necessity of the process assessment in terms of evaluating the three-dimensional etched volume rather than the etched depth. This will potentially solve the non-linearity behaviour and the pattern dependency problem. The optimum etching recipe yields approximately a total volume of 0.354 mm3 through the proper patterning mask. The resultant parabolic cavities have 75 and 13 μ m in their diameter and depth, respectively, as required for the proposed structure. The integration of a microparabolic reflector with such detectors will potentially enhance the specific detectivity of these detectors.

In this study, MWCNTs were used as a filler for epoxy thin film composites, where the thin film was fabricated using the spin coating method. We investigated the dielectric properties of the MWCNT-filled epoxy composite, with filler loading in the range from 0 to 1.5 vol%. Additionally, the effect of various type of MWCNT filler treatments using polyoxyethylene octyl phenyl ether (Triton X-100), sodium dodecyl sulfate (SDS) and 3-aminopropyltriethoxy silane (AMPTES) on the dielectric properties of epoxy thin film composites were investigated. The results showed that the increment of MWCNT loading increased the dielectric properties of the composite system. Meanwhile, chemically treated MWCNTs, especially MWCNT treated with SDS, showed good dielectric properties. Furthermore, morphological study showed an improvement in the dispersion of filler throughout the epoxy matrix in the treated composite system compared to the untreated system. TEM images also showed that treated MWCNT filler increased wall thickness of nanotube.

This paper presents the development of a novel one-side-electrode-type fluidic-based capacitive pressure sensor. A pressure sensor using a one-side-electrode and an implementation of electrical double layer capacitance concept was proposed. Mechanical analysis of the membrane was carried out using the finite-element analysis in terms of deflection and Mises stress. A sensor with a circular membrane radius of 3.2 mm, membrane thickness of 0.8 mm, microchannel thickness of 0.5 mm, and microchannel width of 0.5 mm was fabricated using polydimethylsiloxane. The validation was made between the analytical and experimental results for fluid mechanisms inside the sensor. This showed that the displacement for all types of liquid, including methanol, ethanol, and silicon oil was linearly aligned. Methanol was chosen as an electrolyte due to its liquid properties, such as low surface tension and dielectric permittivity. From the experimental results, the operating frequency, response time, and sensitivity of the sensor were 1.2 kHz, 0.12 s, and 0.77 pF/kPa, respectively. The effects of vibration, temperature, and lifetime were also discussed in this paper.

The dome-shaped membrane was designed for the fluidic based flow sensor for the underwater sensing. It has the diameter of 5mm and thickness within 0.2mm. The simple fabrication process for the dome shaped structure was demonstrated using casting and molding processes. The effect of the fabrication process was investigated by measuring the thickness of the dome-shaped membrane for different sample. For the performance analysis, the actual shape which was the same with the fabricated shaped was simulated and compared with the ideal shape using finite element analysis for the same input flow rate. The membrane sensitivity of the actual shape decreased from 163.4 μm/ms-1 to 133.33 μm/ms-1 compared to the ideal shape based on the displacement of the membrane over input fluid velocity.

The dome-shaped membrane is very important part of the micro/nano devices. The dome-shaped with the thickness of 150 μm and a radius of 3.2 mm was fabricated using the soft lithography process. The Polydimethylsiloxane (PDMS) was selected as a material because it deformable and suitable to implement as a membrane. Soft lithography is based on pattern transfer using a mold that is patterning the substrate material. In this paper, two techniques were suggested to fabricate the dome-shaped membrane which are reflow technique and stamping technique. The comparison was made for both techniques using a Scanning Electron Microscope (SEM) and it seems the stamping technique has an advantage where the uniform thickness of the dome-shaped membrane can be achieved. The discussion on the temperature effect of a stamping technique shows that the suitable temperature to harden the PDMS is in temperature room where the bubbles can be eliminated under this temperature.

The current work investigates the use of liquid polydimethylsiloxane (PDMS), with a 10:1 ratio of prepolymer:curing agent = 10:1 as the intermediate layer for adhesive bonding with Flame Retardant 4 (FR4). The spin coating of liquid PDMS on FR4 allows irreversible adhesive bonding with the solid PDMS. The strength of the proposed adhesive bonding technique has been investigated under different treatment temperatures: oven-heated at 60 °C, 70 °C, and 80 °C, cooled down in the room temperature of 25 °C, and exposed to direct sunlight at 35 °C. All the samples were left for 6 h. Investigations were conducted to analyze the effect of FR4 surface roughness on the strength and quality of the adhesive bonding. The standard procedure of American Standard Test Measurement (ASTM) D1002 was followed to verify the strength of PDMS-FR4 adhesive bonding. Strongest adhesive bonding, free from air bubbles, was obtained from a sample with smooth surface of FR4 that has undergone a cooling down treatment in the room temper...

Presented is an SU-8 microcantilever sensor with integrated piezoresistors made of a mixture of SU-8 polymer and silver nanoparticles. The resulting composite is a spin-coatable and ultraviolet patternable conductive polymer, which can be easily incorporated with any SU-8-based microdevice. The microfabrication technique used in this work is based on adhesive bonding of the cantilever layers with the thick support base to obtain a three-dimensional structures device, which is a cost-effective and fast fabrication process. Based on the current-voltage ( I - V ) test, the fabricated piezoresistors exhibit a linear resistance characteristic with good conductivity. The gauge factor calculated from the deflection test was obtained to be as high as 26.3, demonstrating the capability for embedded SU-8/Ag piezoresistors to improve sensitivity when using polymeric material as a sensor platform.

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Over the years, new discoveries have led to new applications, often taking advantage of their unique electrical properties, extraordinary strength and efficiency in heat conduction. Since industrialisation, human activities have resulted in steadily increasing concentrations of the greenhouse gases. Excess amount of carbon dioxide (CO2) in living environment is toxic and unsuitable for human consumption. Thus, a need exists for accurate, inexpensive, long-term monitoring of environmental contaminants using sensors that can be operated on site. Over the past decade, many wireless sensor network (WSN)-based monitoring applications have been proposed. This article reviews the developments of sensing elements to monitor CO2 in the environment. The cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science,...

This study is the first to demonstrate dimensional optimization of nanowire-complementary metal-oxide-semiconductor inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on both dimensions ratio and digital voltage level (Vdd). Diameter optimization reveals that when Vdd increases, the optimized value of (Dp/Dn) decreases. Channel length optimization results show that when Vdd increases, the optimized value of Ln decreases and that of (Lp/Ln) increases. Dimension ratio optimization reveals that when Vdd increases, the optimized value of Kp/Kn decreases, and silicon nanowire transistor with suitable dimensions (higher Dp and Ln with lower Lp and Dn) can be fabricated.

Drain-induced barrier lowering (DIBL) is crucial in many applications of silicon nanowire transistors. This paper determined the effect of the dimensions of nanowires on DIBL. The MuGFET simulation tool was used to investigate the characteristics of the transistors. The transfer characteristics of transistors with different dimensions were simulated. The results show that longer nanowires with smaller diameters and lower oxide thickness decrease DIBL and tend to possess the best transistor characteristics.

Despite its excellent performance in microelectronic industry, silicon was not able to perform well in photonic devices arena. This is because the silicon has never been a good optical source mainly due to its indirect band gap structure. Many of the device functionalities in silicon have been reported, with an exception of – until recently – a reliable optical source. Silicon is a nonlinear material which makes use of its nonlinearities to realize various functionalities. This paper presents a theoretical treatment of generating and enhancing third-harmonic field which may be used as optical source, crystal state monitoring and all-optical signal processing applications.

The current paper presents an improved bandgap voltage reference (BGR) that utilizes curvature-corrected current generators which compensate for the voltage reference at lower and higher temperature range. The voltage reference is operated with a supply voltage of 2.5V to achieve an output reference of 1.1835V. The temperature coefficient achieved from the circuit is 1.342ppm/°C, resulting from temperature changes between -50°C to 125°C, sixfold improvement from first-order BGR. The proposed circuit is simulated using Silterra 0.13µm CMOS technology.

Silicon or glass was a common material for SU8 coating. However, these materials are hard and brittle, make it difficult for drilling and dicing. This paper reported the effect of grayscale and resolution based on the various length of time for Propylene Glycol Methyl Ether Acetate (PGMEA) developing towards SU8-10 coated on polymethylmethacrylate (PMMA). The grayscale results show that the 0% (solid black) produced the highest percentage on the square structure formed to the SU8-10 film coated on PMMA and the highest resolution had been produced for the 30 minutes of PGMEA developing.

This study is the first to demonstrate characteristics optimization of nanowire resistance load inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on resistance value. Increasing of load resistor tends to increasing in noise margins until saturation point, increasing load resistor after this point will not improve noise margins significantly.

This paper presents the temperature characteristics of a silicon nanowire transistor and its use as a temperature sensor. The OMEN nanowire simulation tool was used to investigate the temperature characteristics of the transistor. Current–voltage characteristics with different values of temperature for three orientations were simulated. The metal–oxide–semiconductor (MOS) diode connection suggests the use of the silicon nanowire transistor as a temperature nanosensor. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

This paper demonstrates the experiment for the capacitive pressure sensor for the fluid mechanism and effects of liquid to the sensor performance. The sensor using one side electrode was proposed with the implementation of electrical double layer capacitor. The sensor consisted of membrane and microchannel where it was fabricated using PDMS material. This sensor was able to measure the pressure below than 7 kPa. When the pressure was applied to the membrane, it gave deflection and the liquid inside the microchannel moved opposite the membrane. The liquid movement gives capacitance change to the sensor where it depends on the types of liquid used. The comparison was made between the experimental and analytical results for the liquid displacement inside the microchannel. In order to study the effect of liquid to the capacitance change, the methanol, ethanol and silicon oil were chosen. When related to the capacitance, the important factor for liquid is dielectric constant. It is proved that the methanol which has higher dielectric gives high performance compared to the ethanol and silicon oil. Given that the sensor sensitivity for the methanol and ethanol were 0.98 pF/kPa and 0.55 pF/kPa, respectively.

This paper presents the characterization of a micro-cyclone combustor that burns liquefied petroleum gas. The combustor is made of stainless steel and has a reaction chamber volume of 1.15 cm3. Fuel and air are mixed inside the chamber by injecting the fuel perpendicularly to the tangentially injected air. The experiment demonstrates that the flame is sustained inside the micro-combustor over a wide range of fuel flow rates and equivalent ratios. The shapes of the flame are visualized experimentally, and the results indicate that different equivalent ratios produce different flame shapes. Combustion stability measurement exhibits that combustion blowout limit decreases as fuel flow rate increases from 10 sccm to 100 sccm, Wall temperature measurement shows that an equivalent ratio of 1.0 produces the most uniform temperature distribution.

This paper presents the novel fluidic based capacitive pressure sensor. The electrical double layer capacitor (EDLC) concept was applied as a sensing method. The methanol was selected as an electrolyte due to its liquid properties such as low surface tension and dielectric permittivity. The circular membrane and microchannel were fabricated using PDMS material and the one side electrode was fabricated on the printed circuit board (PCB). PDMS was used as an insulator on the electrode to allow the formation of the ionic layer. The value of capacitance depends on the liquid movement inside the microchannel. The result of membrane deflections for PDMS membrane with dimension 2.8mm×2.8mm×1.5mm deviated compared to the simulation where it was assumed that the simulation model is was linear. From the experimental results, the operating frequency, response time and sensitivity of the sensor were 1.2 kHz, 0.21 s and 0.033 pF/kPa, respectively.

This paper proposed a novel tunable MEMS solenoid inductor. This tunable solenoid inductor benefits from a liquid-injected core which varies the permeability of the core corresponding to the level of injection of the liquid; hence, the change in permeability of the core causes the change in the inductance. In this work, HFSS is used for 3D EM simulation. The proposed Solenoid inductor is simulated in Silicon substrate with Copper metal as the coil and injected salted water (CaCl2 solved in water) as the solenoid core. The similar previous works for tunable MEMS inductor employing ferromagnetic cores and liquid-based spiral inductors could not exceed an operating frequency of 2 GHz and a Q factor of 12. Here, a maximum Q factor of 18 and tuning range of 60% were achieved at 18 GHz. Also, the implementation procedure of the proposed variable solenoid inductor is simpler and more cost-effective than the other works.

This paper presents the development of the novel fluidic based one side electrode pressure sensor. The structure of the sensor consists of container and an electrode. For the container, the membrane and microchannel were combined in one structure. Meanwhile, the design of the electrode was extended from the pattern of coplanar electrode based on the previous study. The microfluidic technology by using a small amount of liquid as a sensing element was proposed to measure the external pressure. When the external pressure was applied to the sensor, the membrane was deflected and the liquid displaced inside the microchannel. The sensing electrode measured the changes using electrical double layer concepts and gave the output in capacitance. The sensor was successfully fabricated for electrode using printed circuit board (PCB) process and the container using polymer fabrication process. The polymer such as PDMS was chosen because it was suitable to be implemented as a membrane. The methanol was used as a liquid due to its dielectric constant. The data experiment was recorded and measured using LCR meter for different applied pressure. The capacitance response was demonstrated for pressure 2kPa until 30kPa. The sensitivity of the sensor was 0.06pF/kPa. Also, the standard deviation of output capacitance equaled to 0.04.

The simplicity associated with piezoelectric micro-generators makes them very attractive for MEMS applications in which ambient vibrations are harvested and converted into electric energy. These micro-generators can become an alternative to the battery-based solutions in the future, especially for remote systems. In this paper, we propose a model and present the simulation of a MEMS-based energy harvester under ambient vibration excitation using the COVENTORWARE2010 approach. This E-shaped cantilever-based MEMS energy harvester that operates under ambient excitation in frequencies of 28, 29, and 31 Hz within a base acceleration of 1g produces an output power of 0.25 milliwatts at 5kΩ load.

This paper presents simulations of a vibration based piezoelectric raindrop energy harvester to investigate design parameters that directly affect the performance of the device. Combination of diaphragm and cantilevers is considered for the study and the device is simulated using CoventorWare of multi physics finite element analysis. Polyvinylidene fluoride is used as piezoelectric material due to non-toxic characteristic and easiness to shape into sturdy panels, whereas Aluminium as the electrode. The effects of design parameter such as thickness of piezoelectric material, displacement during vibration and maximum pressure applied on the performance of the device are analysed. Results show that the thickness of these materials played a significant role in displacement and output power.

The ambient vibration-based micro electromechanical systems (MEMS) piezoelectric harvester has become an important subject in most research publications. Providing a green and virtually infinite alternative power source to traditional energy sources, this harvester will significantly expand the applications of wireless sensor networks and other technologies. Using piezoelectric materials to harvest the ambient vibrations that surround a system is one method that has seen a dramatic rise in the power-harvesting applications. The simplicity associated with piezoelectric micro-generators makes them very attractive for MEMS applications in which ambient vibrations are harvested and converted into electric energy. These micro-generators can become an alternative to the battery-based solutions in the future, especially for remote systems. In this paper, we propose a model and present the simulation of a MEMS-based energy harvester under ambient vibration excitation using the COVENTORWARE2010 approaches. This E-shaped cantilever-based MEMS energy harvester that operates under ambient excitation in frequencies of 12.8, 17.1, and 21.3 Hz within a base acceleration of 1 m/s2 produces an output power of 1.0 W at 2kO load.

This paper presents the temperature characteristics of silicon nanowire transistors (SiNWTs) and examines the effect of temperature on transfer characteristics, threshold voltage, I(ON)/I(OFF) ratio, drain-induced barrier lowering (DIBL), and sub-threshold swing (SS). The (MuGFET) simulation tool was used to investigate the temperature characteristics of a transistor. The findings reveal the negative effect of higher working temperature on the use of SiNWTs in electronic circuits, such as digital circuits and amplifiers circuits, because of the lower I(ON)/I(OFF) ratio, higher DIBL, and higher SS at higher temperature. Moreover, the ON state is the optimum condition for using a transistor as a temperature nano-sensor.

This paper represents the temperature characteristics of silicon nanowire transistor of rectangular cross-section, temperature effect on transfer characteristics, I ON /1 oFF ratio and sub-threshuld swing was studied. OMEN nanowire simulation tool was used to investigate temperature characteristics of transistor with three types of orientations. The findings of the current study reveal that and are the best types of orientations to be used in SiNWT for the temperature application of electronic circuits, such as digital circuits and amplifiers, because of the high I ON /1 oFF ratio and lower SS at these orientations. Moreover, the best orientation for temperature sensor was because of the larger carrier velocity and smaller channel resistance.

This paper shows the effect of the dimensions of nanowires on threshold voltage, ON/OFF current ratio, and sub-threshold slope. These parameters are critical factors of the characteristics of silicon nanowire transistors. The MuGFET simulation tool was used to investigate the characteristics of a transistor. Current-voltage characteristics with different dimensions were simulated. Results show that long nanowires with low diameter and oxide thickness tend to have the best transistor characteristics.

This paper presents the investigation results of low actuation voltage for RF MEMS capacitive switches using three electrodes topology. The main purpose of the investigation is to verify the reduction of actuation voltage as a result of applying three electrodes in RF MEMS. The new switch structure emphasizes three parallel electrodes instead of two electrodes as in previous structure. In the design stage all performance factors include beam width, beam length, area and beam thickness have been optimized to ensure the best physical dimension of the switch. The investigation of the performance was carried out using Architect Coventorware. Preliminary results shows that the actuation voltage of the three parallel electrodes switch gives very significant reduction of actuation voltage which is approximately half compared to other topologies or standard structure using two parallel electrodes.

This paper highlights an effort to study the characteristics of silicon CMOS nanowire transistor and the effect of cross-sectional area of PMOS transistor on silicon nanowire-CMOS inverter characteristics. In this study generated MATLAB code is used together with NanoHub MuGFET simulation tool to produce the characteristics of silicon nanowire transistors and nanowire CMOS inverter. Nanowire CMOS inverter was simulated and investigated using MuGFET simulation tool and designed MATLAB code to calculate the output and current characteristics of inverter. The best transfer characteristics for inflection voltage (near to half input voltage) was obtained by increasing the diameter of nanowire of P-channel transistor because of lower mobility of carriers (holes) in P-channel nanowires compared to the carriers (electrons) in N-channel nanowire transistor.

The market for wireless sensor networks (WSNs) is rapidly growing, yet limited by batteries with short lifetimes. Providing a green, virtually infinite alternative power source to traditional energy sources will significantly expand the applications for WSNs and other technologies. The use of piezoelectric materials to capitalize on the ambient vibrations surrounding a system is a method that presents dramatic potential for power harvesting. The simplicity associated with piezoelectric micro-generators makes MEMS applications highly attractive. In such applications, mechanical vibrations from environment are harvested and converted into electrical energy. These micro-generators are designed as an alternative to a battery-based solution that is especially intended for remote systems. We propose a comparative study on the obtained results of the energy delivered from the ambient vibration-based MEMS energy harvester using the ANSYS and COVENTORWARE approaches. The improvement reflected in the experimental results for vibration-based MEMS piezoelectric energy harvesters indicates excellent application scope in power MEMS and green energy.

This paper presents the analysis of modeling for artificial lateral line flow sensor. An artificial hair cell sensor is the current technology that based on a biological inspiration and widely used in underwater applications including glider, robotic and autonomous surface vehicle (ASV). The structure of the lateral line flow sensor is consisting of cantilever beam and four hair cells attached perpendicular to the cantilever beam at the free end. The lateral line sensor with different height of hair cells are modeled and simulated with water flow rate 0 m/s to 1 m/s. High sensitivity is achieved by increasing a hair cells length and use low young modulus material for a cantilever beam. The maximum stress was analyzed in order to identify the limitation of the sensor.

This paper represents the temperature effect on silicon nanowire transistor and the possibility of using it as a temperature nanosensor. MuGFET simulation tool was used to investigate temperature characteristics of the nanowire transistors. Current-voltage characteristics with different values of temperature were simulated. Variation of sub threshold slope (SS), ON current to OFF current ratio (Ion/Ioff) and drain induced barrier lowering (DBIL) with working temperature was investigated. MOS diode connection suggested using the silicon nanowire transistor as a temperature nanosensor.

This paper is to study the characteristics of nanowire-CMOS and effect of increasing of numbers of nanowires in transistors on the nanowire-CMOS characteristics. This study used MuGFET simulation tool to produce the characteristics of nanowire transistors and used as input to MATLAB software to produce the characteristics of nanowire-CMOS. Increasing channel nanowires in P-channel transistor tends to improve the transfer characteristics of CMOS. Increasing channel nanowires in N-channel transistor tends to poorer transfer characteristics of CMOS.

The design and simulation of an MEMS-based capacitive bending strain sensor using silicone dope as a plate is presented in this paper. The objective is to design and simulate the performance of a strain sensor using a dielectric material between capacitive plates. The silicone dioxide (SiO 2 ) and polydimethylsiloxane (PDMS) was utilized as the dielectric layer in this model. Several dimensions of the sensor and the dielectric materials were studied as silicon dioxide was also used to increase the performance of the sensor. The application of the sensor is for the spinal fusion monitoring system. The finite element analysis (FEA) was performed using MEMS CoventorWare 2008, and the results were verified using the analytical method. Based on simulation results, the presences of the dielectric material has increased the capacitance output of the sensors and produced greater sensitivity. The sensitivity of the sensor is 24.9–44.48% higher compared with existing sensors. The nominal capacitance of the sensor also improved significantly from 94.16pF to 156.14pF. The sensor also exhibits greater sensitivity at the early stage of the bending strain; the sensitivity of the sensor is up to 0.525pF/μe.

Temperature uniformity on a micro-hotplate is important for gas sensor sensitivity, linearity, and resolution. There are several ways to create a uniform temperature distribution on a micro-hotplate. In this paper, the modification of microheater geometry is the method used. Four different heater geometries are simulated using ConvetorWare software to determine which geometry can give the most uniform temperature distribution. The simulations show that the heater geometry which combines parallel and meander shapes results in the most uniform heat distribution. The electrical potential and current distributions of the four different micro-heater geometries are also evaluated.

The effect of material, thickness and the magnitude of heat generated by microcombustor on heat distribution along thermal spreader for thermoelectric power generator are investigated. Impact of various materials and physical properties was studied upon sample 3 cm × 3 cm. The effect of thermal conductivity, specific heat capacity and thickness towards temperature uniformity of thermal spreader is observed. The result provides temperature profile of the thermal spreader dependencies of the source of heat. Results show that copper is the best thermal spreader material for thermoelectric power generator.

A novel fabrication technique using polymethylmethacrylate (PMMA) as a base material for SU8-10 film coating is to be discussed in this paper. The SU8-10 coated onto PMMA is used as a mold to fabricate PDMS relief. The SU8-10 mold has been tested for a square structure and various types of line resolutions. Propylene Glycol Methyl Ether Acetate (PGMEA) developing towards SU8-10 coated on PMMA for 2 hours is suitable for a 5mm × 5mm square structure whereas PGMEA developing for 30 minutes is found to be suitable to produce the smallest resolution of 2mm. The results have proven that PMMA is a promising material to be used as SU8-10 mold despite silicon or glass, two materials which have been commonly used for SU8-10 mold. PMMA in its natural structure is flexible, making it easy to drill and cut. Other advantages of PMMA lie in the facts that it is cheap, transparent and biocompatible.

A simple fabrication method on wet etching and thermal evaporator had been used to fabricate microfluidic three gold (Au) electrodes assembled with polydimethylsiloxane (PDMS) was reported in the present work. In this work, we studied the suitable size of electrode area that can fulfill the Randle-Sevcik equation for reversible redox process. The voltammograms of 0.01 M K 3 Fe(CN) 6 in 0.1M KCl at 1.04 mm2 electrode area demonstrates the current peak ratio of unity thus suitable to be further developed as a three electrode sensory system with Ag/AgCl reference electrode. The plotted graph for peak current vs electrode area satisfied the Randle-Sevcik equation as well. Cyclic Voltammetry (CV) analysis proved that the fabricated sensor was reliable in the range of 24 hours at the room temperature of 25°C.

Sulfate reducing bacteria (SRB) is a nonpathogenic and anaerobic bacterium which can produce enzyme to accelerate the reduction of sulfate compounds to hydrogen sulphate that corrodes metal. This paper will study the possibility of using electronic nose which consists of chemical sensing system, data acquisition system and pattern recognition system such as artificial neural network to detect hydrogen sulphide. There are a few methods of detecting SRB such as laboratory analysis and field test kit but the procedures are costly and take longer time, within 1 to 2 days. Study shows that electronic nose can be used to detect SRB by detecting hydrogen sulphide that is produced during reduction process. The electronic nose can detect hydrogen sulphide within 16 hours where the detection period is reduced from 30% to 65%. Study also shows that the electronic nose with micro hotplate sensor base will reduce 86% of power consumption compared to electronic nose with alumina ceramic sensor base.

In this paper, we proposed a sealing technique for a sealing glass cap with a ceramic substrate by using silica coating liquid to increase the performance of fluid-based inclination sensor in heat-resisting and durability characteristic. The sensor was developed with one-side-electrode-type structure and propylene carbonate was used as electrolyte. The sensor uses capacitance change to detect the angle of inclination, and it is capable measuring inclination at supply voltage 1.5 V. The diameter of glass cap and height were 4.0 mm and 2.0 mm, respectively. The linearity of characteristic can be improved when the supply voltage was set at 1.5 V. The sensitivity, response time and resolution of sensor were 4 mV/deg, 0.6 s and 1.8 deg, respectively at the supply voltage 1.5 V. The temperature characteristic was evaluated between −10 °C to 50 °C.

This study presents the behavior of a micro cantilever beam accelerometer under electrostatic actuation by using the analytical and numerical method. The objective of this study is to determine optimal design of capacitive micro cantilever beam accelerometer in term of reducing the beam deflection with respect to applied acceleration but keeping the distance between electrodes. The structure contains proof mass which is suspended between fixed rigid electrodes to provide differential capacitance measurements. ANSYSO is used for finite element analysis (FEA) modeling and simulation. The analytical modeling is done by using C programming. Three dimensional modeling is done for six different loading conditions in order to come out with the optimal design. The results obtained from both the analytical and finite element models are found to be in excellent agreement.

The purpose of this paper is to present the analysis of electrostatic actuated microrelay with four terminals, single-pole, single-throw, and normally-open device with bridge contact (SPST-NO-Bridge) via simple analytical modeling and Finite Element Method (FEM). The behavior of the device has been simulated using electrostatic, mechanical and dynamic analysis. The results obtained by FEM and analytical analysis are in good agreement. Through optimization process of the physical structure, the total size of the device (without bondpads) is about 220 x 220 µm2, which is suitable for high integration circuitry. The results shows that minimum switching voltage is 17V with operating voltage of 24V and the device can go up to 2 KHz of switching frequency.

In this paper, we propose a method that can measure the shallow trench isolation (STI) stress effect on transistor in the direction of channel width. Instead of implanting the entire channel (fixed width of 10um), we only implant one portion of the channel (with fixed implant opening width of 0.5um). By using this method, the channel edge can be brought away from the STI edge, where the active area is under high compressive stress. The results show that when the effective channel is near to the STI edge (high transverse compressive stress), both NMOS and PMOS transistors have higher threshold voltage, Vt and lower drain current, Id.

We investigate the 130nm (1.2V) and 280nm (2.5V) CMOS linear threshold voltage (Vtlin) and normalized saturation drain current (Idsat) versus channel width. Plots of Vtlin and Idsat versus channel width for different lengths are used to show the complex behavior as the channel width decreases. Both NMOS and PMOS Vtlin reach a maximum and then decrease as the width goes to W = 0.15/spl mu/m. NMOS Vtlin shows a 30% decease while PMOS Vtlin decreases 5% to 18%. We then show that the Vtlin behavior is caused by two opposite factors, shallow trench isolation (STI) y-stress effect and inverse narrow width (INW) effect. We eliminate x-stress as a factor by designing all the transistors with Sa = 10/spl mu/m. We observe that NMOS and PMOS Idsat decrease as the width decreases from 20/spl mu/m to 1/spl mu/m reaching a minimum, after that Idsat increases again. We believe this Idsat behavior is also caused by two opposite factors, STI y-stress effect and delta width, DW effect. The Idsat behavior is different for NMOS and PMOS. The STI y-stress effect is less pronounced for short channel NMOS transistors while the DW effect is weaker for short channel PMOS transistors.

In this paper, we investigated the compressive mechanical STI x-stress (in the direction of channel length) on channel width. When the channel width becomes narrower, the compressive STI y-stress effect become more severe and causes STI x-stress has lower effect on NMOS Idsat but has higher effect on PMOS Idsat. This means that the amount of NMOS Idsat decrement due to x-stress become less but the amount of PMOS Idsat increment due to x-stress become higher when y-stress increases (narrower channel width)

This paper deals with the theory, fabrication and test results of an ultrasonic technique which is used to measure vacuum in a container. Ultrasonic transmitter and receiver, working at 40 KHz, are used for conducting the experiments. The sensitivity of measurement is a function of applied voltage to the transmitter. Results on a prototype model are included and relationship between output voltage and pressure is appreciably linear.

The ion-sensitive field effect transistor (ISFET) based pH sensor has the advantages of smaller size, fast response time and fabrication compatible with standard MOS technology. Beside that, the functionality of pH ISFETs is various especially in biomedical areas. In the design and characterization of an ISFET pH sensor, the ISFET model was characterized and a final design has been evolved with the assistance of the Tanner tools software. To provide a better understanding' of pH ISFET as a biosensor, the C-V characteristics, temperature dependence of the ISFET and pH sensitivity of electrolyte-insulator-semiconductor in response to different pH are examined. The insulator, aluminium oxide (AI/sub 2/O/sub 3/) has been applied as a pH sensitive layer. The ISFET is matched with a metal oxide field effect transistor (MOSFET) at the differential input stage of a CMOS operational amplifier and realized in a 0.8 um CMOS technology. From the output of ISFET operational amplifier, the pH sensitivity is approximately 54.8 mV per pH.

This paper presents the design and development of an odour sensing system based on a quartz crystal microbalance (QCM) odour-sensor array and an artificial neural network (ANN) for the identification of some of the volatile organic compounds (VOCs) such as acetone, benzene, chloroform, ethanol and methanol. The QCM sensors were developed using PVC-blended lipids as sensing materials. A home-built data acquisition and embedded pattern recognition system were developed using the Xilinx IC and AT89C52 microcontroller. In addition, user interface software was developed to control the vapours flow system, data acquisition, process the acquired data and display the detected vapours using optimised neural network. The performance of this odour sensing system for VOCs emission detection was tested under laboratory conditions to determine its ability to detect single odour compound emission. Simulation and experimental results using an optimised neural network system confirmed that the proposed odour recognition system was effective in identifying the tested VOCs

Mechanical compressive stress induced by shallow trench isolation (STI) and transistor mismatch is the two important effects that we should take into account when scaling down CMOS transistors. In this paper, we study the relationship between these two effects. Our finding shows that STI induced stress effect improve NMOS Id matching but degrade PMOS Id matching. These effects become more obvious for small size transistors. The STI stress effect has no significant effect on V/sub t/ mismatch.

Biodegradable sago starch-filled natural rubber latex films were subjected to soil decomposition. Decomposition indicators such as temperature, soil pH and humidity, and volume of carbon dioxide and oxygen were monitored via an electronic sensor network (ESN) control chamber. During the assessment, the environmental temperature was kept constant and a small increase in soil humidity was detected. The ESN control chamber detected the increment of soil pH and carbon dioxide level and a decrease in oxygen content during the biodegradation process. The changes in these parameters confirmed the progress of the biodegradation process. The mass loss retention for films was compared with data obtained from the ESN control chamber to get the coefficient of correlation (r) value, which describes the relationships between the two datasets. Scanning electron microscopy images confirmed the formation and growth of microorganism colonies, and Fourier transform infrared analysis indicated the breakage of double-bonded carbon in sago starch-filled natural rubber latex films and carbonyl group intensification, signifying the formation of aldehyde and ketone groups after the fourth week of soil decomposition.