P1MM.5 - Optimization of Silicon and Quartz MEMS Microheater for Chemoresistive Gas Sensors (original) (raw)
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MEMS-based microheaters integrated gas sensors
Integrated Ferroelectrics, 2018
In the present work efforts have been made to develop microheater integrated gas sensors with low power consumption. The design and simulation of a single-cell microheater is carried out using ANSYS. Low power consumption (<35 mW) platinum micro-heater has been fabricated using bulk micromachining technique on silicon dioxide membrane (1.5 lm thin), which provided improved thermal isolation of the active area of 250 Â 250 lm 2. The micro-heater has achieved a maximum temperature of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof950 C at an applied dc voltage of 2.5 V. Fabricated mircro-heater has been integrated with SnO 2 based gas sensors for the efficient detection of H 2 and NO 2 gases. The developed sensors were found to yield the maximum sensing response of 950Catanapplieddcvoltageof2.5V.Fabricatedmircro−heaterhasbeenintegratedwithSnO2basedgassensorsfortheefficientdetectionofH2andNO2gases.Thedevelopedsensorswerefoundtoyieldthemaximumsensingresponseof184 and $2.1 with low power consumption of 29.18 and 34.53 mW towards the detection of 1 ppm of NO 2 gas and 500 ppm of H 2 gas, respectively.
Design of the optimum microheater for smart MEMS gas sensor
Conventional Metal Oxide gas sensors commonly used for sensing inflammable hydrocarbon gases and other toxic gases. However, they suffer from the two limitations, viz. (a) their relatively high operating temperature (≥300° c) and (b) large power dissipation (≥1 Watt). Micromachined silicon based metal oxide gas sensors are being developed to overcome these limitations.The main part of power consumption in a micro-machined gas sensor consists of various thermal losses like conduction through bulk silicon substrate, convection in air from all exposed surfaces and radiation. The thermal characteristics of micro-machined metal oxide based gas sensors have to be optimized with respect to low power consumption, well controlled temperature distribution over the sensing layer and fast transient response. However microheater for the MEMS metal oxide gas sensors have not yet been optimized. In this paper we have developed a methodology (software) for designing and optimizing microheater for MEMS based gas sensor. Using this software we can estimate power requirement for achieving a particular temperature as well as the temperature distribution over the active layer.
Sensors
The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane ...
Data, 2021
Over the last few years, employment of the standard silicon microfabrication techniques for the gas sensor technology has allowed for the development of ever-small, low-cost, and low-power consumption devices. Specifically, the development of silicon microheaters (MHs) has become well established to produce MOS gas sensors. Therefore, the development of predictive models that help to define a priori the optimal design and layout of the device have become crucial, in order to achieve both low power consumption and high mechanical stability. In this research dataset, we present the experimental data collected to develop a specific and useful predictive thermal-mechanical model for high performing silicon MHs. To this aim, three MH layouts over three different membrane sizes were developed by using the standard silicon microfabrication process. Thermal and mechanical performances of the produced devices were experimentally evaluated, by using probe stations and mechanical failure analy...
Sensors and Actuators B: Chemical, 1996
The stable and low-power heating characteristics of a microheater are very important for the micro gas sensor. Membrane-type gas sensors have been fabricated by silicon IC technology. Steady-state thermal analysis by the finite-element method is performed to optimize the thermal properties of the gas sensor. From the analysis, the desirable size of the microheater for low power consumption is determined. The heating properties of fabricated poly-Si and Pt microheaters have been tested. The sensing characteristics of the packaged microsensor are also examined.
Silicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form
Chemosensors
A reduced size thermocatalytic gas sensor was developed for the detection of methane over the 20% of the explosive concentration. The sensor chip is formed from two membranes with a 150 µm diameter heated area in their centers and covered with highly dispersed nano-sized catalyst and inert reference, respectively. The power dissipation of the chip is well below 70 mW at the 530 °C maximum operation temperature. The chip is mounted in a novel surface mounted metal-ceramic sensor package in the form-factor of SOT-89. The sensitivity of the device is 10 mV/v%, whereas the response and recovery times without the additional carbon filter over the chip are <500 ms and <2 s, respectively. The tests have shown the reliability of the new design concerning the hotplate stability and massive encapsulation, but the high degradation rate of the catalyst coupled with its modest chemical power limits the use of the sensor only in pulsed mode of operation. The optimized pulsed mode reduces th...
Chemosensors
The design of the heater plays a decisive role in the energy consumption, sensitivity, and speed of chemical sensors. The paper analyzes various options for the topology of meander-type platinum heaters in chemical sensors fabricated on thin dielectric membranes using MEMS-silicon technology. Comprehensive studies of the heater’s current–voltage characteristics have been carried out, heating rates have been measured at various currents, experimental temperature characteristics for various meander topologies have been obtained, heater options have been determined, and optimal heat transfer processes are ensured at a low power consumption of about 20–25 mW. Sensors with an optimal heater topology based on a double dielectric membrane were fabricated according to the described technological process, and sensory responses to 0.5 vol.% CH4 and 0.2% C3H8 were studied. The obtained results showed good results and confirmed the need to choose the optimal heater topology when designing senso...
SQI-CMOS based single crystal silicon micro-heaters for gas sensors
2006 5th IEEE Conference on Sensors, 2006
Here we report on novel high temperature gas sensors that have been fabricated using an SOI (Silicon-oninsulator) -CMOS process and deep RIE back-etching. These sensors offer ultra-low power consumption, low unit cost, and excellent thermal stability. The highly-doped single crystal silicon (SCS) layer of a standard SOI-CMOS process, which is traditionally used to form the source and drain regions of a MOSFET, is used, for the first time, to form a resistive heater of a micro-hotplate in a high-temperature gas sensor. Our sensors have a power consumption of only 12-30 mW at a temperature of 500°C. We have observed that the drift in resistance of a SCS heater held at 500°C for 500 hours, without burn-in, was less than 1 %. SCS micro-hotplates are not only suitable for chemoresistive sensors, as described here, but also calorimetric gas sensors that require these high operating temperatures. Tungsten oxide nanorods have been deposited onto our micro-hotplates by atmospheric chemical vapour deposition and have shown reasoanble sensitivity to ethanol vapour in air.