Survivability of a silicon-based microelectronic gas-detector structure for high-temperature flow applications

Patel, Sanjay V.; DiBattista, Michael; Gland, John L.; Schwank, Johannes W.

doi:10.1016/s0925-4005(97)80069-x

Cited by 22 publications

(13 citation statements)

References 4 publications

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“…Thick, freestanding, high aspect ratio microheaters in Si were micromachined for preconcentrators. 13,14 However, a much thicker microheater of 400 m or more for the preconcentrator is needed. To achieve a sensitivity of 10 parts per billion, 2 mg of polymer adsorbent closely attached to the microheaters of the preconcentrator is needed.…”

Section: Introductionmentioning

confidence: 99%

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Freestanding microheaters in Si with high aspect ratio microstructures

Tian

Pang

2002

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inSingle-mask, three-dimensional microfabrication of high-aspect-ratio structures in bulk silicon using reactive ion etching lag and sacrificial oxidation Appl. Phys. Lett. 85, 6281 (2004); 10.1063/1.1834720 Thick and thermally isolated Si microheaters for microfabricated preconcentrators J. Vac. Sci. Technol. B 21, 274 (2003); 10.1116/1.1539065Fabrication and electrical characterization of high aspect ratio silicon field emitter arrays Freestanding, high aspect ratio microstructures in Si were micromachined as thick microheaters. These microheaters, combined with adsorbents, can be used as preconcentrators in a micromachined gas chromatography system. Dry etching of Si using etch and passivation cycles has been developed to produce 240 m thick Si microheaters with 3 m wide wires, achieving a high aspect ratio of 80:1. This optimized dry etching technology results in high etch rates with vertical profiles for thick Si microheaters up to 535 m. Microheaters with 40 m wide wires, 110 m gaps, 400 m thick, and an area of 9 mm 2 have been fabricated. With the heater on a 140 m thick Si membrane, it takes 1320 mW to increase the temperature by 290°C. The power consumption is reduced to 447 mW for the same temperature raise with a freestanding Si microheater. Heating response for freestanding Si microheaters with different thicknesses is also studied. These Si microheaters have fast response times and reach 75% of the final temperature in 5 s. Microheaters consisting of Si wires and posts show similar response time and heating uniformity. In addition, power consumption is reduced by thermal isolation of the microheaters. These thick, freestanding high aspect ratio Si microheaters can provide high power efficiency, large adsorbent capacity, and high mechanical strength.

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Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10][11][12][13][14] These microheaters suffered from heat loss to the membrane. [7][8][9][10][11][12][13][14] These microheaters suffered from heat loss to the membrane.…”

Section: Introductionmentioning

confidence: 99%

Freestanding microheaters in Si with high aspect ratio microstructures

Tian

Pang

2002

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…1,2 These materials are used together in applications such as dynamic random access memory ͑DRAM͒ devices, [3][4][5][6] thin film chemical sensors, [7][8][9][10] and heterogeneous catalysts. 11,12 Each of these applications use Pt and Ti layers of different thicknesses to meet different objectives.…”

Section: Introductionmentioning

confidence: 99%

Determination of diffusion in polycrystalline platinum thin films

DiBattista

Schwank

1999

Journal of Applied Physics

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Grain boundary diffusion of titanium through platinum thin films has been carried out in the temperature range from 200 to 600°C. Five different platinum/titanium bilayer thicknesses, from 35 to 800 Å Pt, were annealed in 5% O 2 /95% N 2 . The accumulation of titanium at the platinum surface layer was measured by x-ray photoelectron spectroscopy ͑XPS͒ to determine the grain boundary diffusion coefficient (D b ). Diffusivity values were calculated based on two different analysis methods assuming type C kinetics. For Pt layers thicker than 200 Å, the activation energy (Q b ) for titanium diffusion was found to be 118Ϯ15 kJ/mol ͑1.22Ϯ0.16 eV͒. For Pt layers thinner than 200 Å, there was a thickness dependence on the diffusion kinetics, resulting in activation energies as low as 20Ϯ4 kJ/mol ͑0.21Ϯ0.04 eV͒. XPS results gave no evidence for any Pt-Ti alloy formation in these layers. The suppression of alloy formation may be attributed to the presence of oxygen at the Pt/Ti interface during layer deposition. The quantitative analysis of titanium interdiffusion in platinum provides valuable information regarding Pt/Ti surface concentrations in thin-film chemical sensors, and for understanding changes in operational characteristics of platinum electrodes.

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“…Thin films of noble metals (platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh)) have widespread applications in various devices such as electrodes for chemical and electromechanical sensors and devices [1][2][3][4][5]. In addition, these noble metal films have found applications in high-temperature sensor applications as the elements for micro-hot plates and electrodes for structural monitoring sensors and thermocouples for harsh-environment energy applications (such as gas turbines and fuel cell systems operated at >500 • C) [6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Platinum–zirconium composite thin film electrodes for high-temperature micro-chemical sensor applications

Çiftyürek

McMillen

Sabolsky

et al. 2015

Sensors and Actuators B: Chemical

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a b s t r a c tStable metal interconnect thin films are critical in the development of various micro-machined devices that may operate continuously at elevated temperatures. The main objective of this work was to investigate the microstructural and electrical stability of a functionally gradient platinum (Pt)-zirconium (Zr) composite thin film electrode designed for resistive-type chemical sensors. Thin film electrodes were fabricated using a DC magnetron sputtering process. Zirconium was used as both the conventional adhesion promoter and the Pt grain modifier within the bulk electrode microstructure. The thin film deposition was completed on highly polished alumina substrates at 200 • C. The various composite Pt thin films were further annealed at 1200 • C after deposition for 1-24 h for rapid evaluation of the microstructure stability. This temperature was chosen since the electrodes are expected to operate beyond 1000 • C for high-temperature MEMS applications. Scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the alterations in chemistry, microstructure and distribution of the constituent elements through the film thickness. The electrical resistivity of the as-deposited and thermally processed Pt thin films was measured by utilizing a van der Pauw's four-point probe technique. The work identified a Zr/Zr + Pt/Pt composite thin film with the 525 nm total film thickness that demonstrated resistivity <5.08 × 10 −7 m after being processed to 1200 • C for 15 h. A lift-off technique was finally used to produce a micro-electrode patterns with the optimized film structure for high-temperature applications.

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Survivability of a silicon-based microelectronic gas-detector structure for high-temperature flow applications

Cited by 22 publications

References 4 publications

Freestanding microheaters in Si with high aspect ratio microstructures

Freestanding microheaters in Si with high aspect ratio microstructures

Determination of diffusion in polycrystalline platinum thin films

Platinum–zirconium composite thin film electrodes for high-temperature micro-chemical sensor applications

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