Fabrication and properties of a Si-based high-sensitivity microcalorimetric gas sensor

Zanini, Margherita; Visser, J.H.; Rimai, L.; Soltis, R.E.; Ковальчук, А. О.; Hoffman, David W.; Logothetis, E. M.; Bonné, U.; Brewer, Leo; Bynum, O.W.; Richard, M.A.

doi:10.1016/0924-4247(95)01000-9

Cited by 49 publications

(30 citation statements)

References 3 publications

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“…By making measurement in static conditions the effect of gas thermal conductivity can be determined. Heat also conducts along the bridge itself, heat loss, q 3 , which is minimized due to the small cross-sectional area of the beam. The highest temperature is expected to occur at the center of the bridge as it is the farthest point from highly thermally conductive solid substrate.…”

Section: Device Design and Principle Of Operationmentioning

confidence: 99%

“…2,3 Microfabricated thermal resistive bridges used for catalyst heater and resistance thermometer have been reported with 0.2 ms response time at even lower power level. 4 Compared with the calorimetric gas sensing principle used in the previous work, an electrothermal sensing mechanism based on the thermal conductivity of gases does not rely on gas adsorption and reaction with catalyst films.…”

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confidence: 99%

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Simulation and Fabrication of an Ultra-Low Power Miniature Microbridge Thermal Conductivity Gas Sensor

Mahdavifar

Aguilar

Peng

et al. 2014

J. Electrochem. Soc.

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A miniature, ultra-low power, sensitive, microbridge-based thermal conductivity gas sensor has been developed. The batch fabrication of the sensors was realized by CMOS compatible processes and surface micromachining techniques. Doped polysilicon was used as the structural material of the bridge with critical dimension of 500 nm. A model of the microbridge was simulated in COMSOL that couples electrical and thermal physics together and includes minimal simplifications. Modeling results shows that the majority of heat is transferred via conduction through the gas gap under the bridge. Heat loss from constant voltage application was observed to be a function of the thermal conductivity of the gas ambient, resulting in different magnitude of resistance change. Maximum temperature occurs at the center of the bridge and could be as high as 800 K. Modeling results coincide with experimental data in predicting resistance changes. The sensor was tested with nitrogen, carbon dioxide, and helium. The response of the sensor to the mixtures of helium fractions in nitrogen was tested. We demonstrated that the sensitivity for helium in nitrogen was 0.34 m /ppm when operated at 3.6 V supplies (at power level of 4.3 mW). With a Wheatstone bridge with ac excitation and a lock-in amplifier the sensor limit of detection was ∼700 ppm helium in nitrogen. The stability of the sensor was excellent achieving over 30 billion measurements before failure. There is an increasing demand and variety of applications for miniaturized gas sensors. Applications range from environment safety sensing, transportation systems, medical and health to aid in diagnostics and even food safety and agriculture. Conventional gas detectors including the most widely used, relatively small pellistors 1 require large power consumption (hundreds of milli-Watts to Watts) with slow response time (tens of seconds). With MEMS technology, microhotplates have been built and are capable of reaching operating temperatures of 500• C in 20 ms at a power level of 100 mW. 2,3 Microfabricated thermal resistive bridges used for catalyst heater and resistance thermometer have been reported with 0.2 ms response time at even lower power level. 4 Compared with the calorimetric gas sensing principle used in the previous work, an electrothermal sensing mechanism based on the thermal conductivity of gases does not rely on gas adsorption and reaction with catalyst films. Therefore, the response speed can be more rapid, and the sensor can be operated in a continuous manner and be repeatedly used without memory effect. Miniature thermal conductivity sensors have been developed for gas chromatography systems 5,6 and demonstrated for methane determination in natural gas.7 Summaries of chemical sensor platforms based on thermal conductivity sensors are provided in references. 8,9 Other groups have investigated nanoscale bridge type gas sensors using chemically synthesized carbon nanotubes, 10 nanowires, 11 and nanobelts, 12 and a review by G. Di Francia et al. 13 has been published. Altho...

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Section: Device Design and Principle Of Operationmentioning

confidence: 99%

mentioning

confidence: 99%

Simulation and Fabrication of an Ultra-Low Power Miniature Microbridge Thermal Conductivity Gas Sensor

Mahdavifar

Aguilar

Peng

et al. 2014

J. Electrochem. Soc.

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“…[1][2][3] While structurally similar to graphite and graphene, h-BN has a distinct set of complementary and, in many cases, advantageous properties compared to its and environmental protection. Research efforts have focused on porous alumina supports, [29][30][31] which suffer from low thermal conductivity, and thin fi lms of catalytic metals, [ 30,[32][33][34] which have low active surface area. Boron nitride aerogel offers enhanced thermal conductivity compared to alumina, and a high surface area for increased nanoparticle loading in a constrained volume of the microfabricated sensor.…”

Section: Introductionmentioning

confidence: 99%

Platinum Nanoparticle Loading of Boron Nitride Aerogel and Its Use as a Novel Material for Low‐Power Catalytic Gas Sensing

Harley‐Trochimczyk

Pham

Chang

et al. 2015

Adv Funct Materials

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A high‐surface‐area, highly crystalline boron nitride aerogel synthesized with nonhazardous reactants has been loaded with crystalline platinum nanoparticles to form a novel nanomaterial that exhibits many advantages for use in a catalytic gas sensing application. The platinum nanoparticle‐loaded boron nitride aerogel integrated onto a microheater platform allows for calorimetric propane detection. The boron nitride aerogel exhibits thermal stability up to 900 °C and supports disperse platinum nanoparticles, with no sintering observed after 24 h of high‐temperature testing. The high thermal conductivity and low density of the boron nitride aerogel result in an order of magnitude faster response and recovery times (<2 s) than reported on alumina support and allow for 10% duty cycling of the microheater with no loss in sensitivity. The resulting 1.5 mW sensor power consumption is two orders of magnitude less than commercially available catalytic gas sensors and unlocks the potential for wireless, battery‐powered catalytic gas sensing.

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“…Other groups have used conceptually similar microcombustor designs to fashion micro chemical reactors for partial oxidation synthesis [1], power generation and hydrogen reforming [2] and gas sensing [3,4,5,6]. For the work described in this report, there were two main goals: demonstrate the use of microcombustors in (a) heating of microanalytical systems, and (b) in the construction of a microFID.…”

Section: Introductionmentioning

confidence: 99%

“…The results of this modeling effort are summarized. Finally, reliable deposition of catalysts is very important for this type of device, and techniques such as slurry deposition [6] and chemical vapor deposition [4,5,9] have been used in the past. In this work, the list of commonly used catalyst deposition methods was extended by using a new micropen deposition technique to reliably, and uniformly, deposit the necessary catalysts.…”

Section: Introductionmentioning

confidence: 99%

A Novel Microcombustor for Sensor and Thermal Energy Management Applications in Microsystems

Manginell¹,

Moorman²,

Colburn³

et al. 2003

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The microcombustor described in this report was developed primarily for thermal management in microsystems and as a platform for micro-scale flame ionization detectors (microFID). The microcombustor consists of a thin-film heater/thermal sensor patterned on a thin insulating membrane that is suspended from its edges over a silicon frame. This micromachined design has very low heat capacity and thermal conductivity and is an ideal platform for heating catalytic materials placed on its surface. Catalysts play an important role in this design since they provide a convenient surface-based method for flame ignition and stabilization. The free-standing platform used in the microcombustor mitigates large heat losses arising from large surface-to-volume ratios typical of the microdomain, and, together with the insulating platform, permit combustion on the microscale. Surface oxidation, flame ignition and flame stabilization have been demonstrated with this design for hydrogen and hydrocarbon fuels premixed with air. Unoptimized heat densities of 38 mW/mm 2 have been achieved for the purpose of heating microsystems. Importantly, the microcombustor design expands the limits of flammability (LoF) as compared with conventional diffusion flames; an unoptimized LoF of 1-32% for natural gas in air was demonstrated with the microcombustor, whereas conventionally 4-16% observed. The LoF for hydrogen, methane, propane and ethane are likewise expanded. This feature will permit the use of this technology in many portable applications were reduced temperatures, lean fuel/air mixes or low gas flows are required. By coupling miniature electrodes and an electrometer circuit with the microcombustor, the first ever demonstration of a microFID utilizing premixed fuel and a catalytically-stabilized flame has been performed; the detection of ~1-3% of ethane in hydrogen/air is shown. This report describes work done to develop the microcombustor for microsystem heating and flame ionization detection and includes a description of modeling and simulation performed to understand the basic operation of this device. Ancillary research on the use of the microcombustor in calorimetric gas sensing is also described where appropriate 4

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Fabrication and properties of a Si-based high-sensitivity microcalorimetric gas sensor

Cited by 49 publications

References 3 publications

Simulation and Fabrication of an Ultra-Low Power Miniature Microbridge Thermal Conductivity Gas Sensor

Simulation and Fabrication of an Ultra-Low Power Miniature Microbridge Thermal Conductivity Gas Sensor

Platinum Nanoparticle Loading of Boron Nitride Aerogel and Its Use as a Novel Material for Low‐Power Catalytic Gas Sensing

A Novel Microcombustor for Sensor and Thermal Energy Management Applications in Microsystems

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