| 1. |
- Berglund, Martin, 1985-, et al.
(author)
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Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
- 2015
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In: Journal of Micromechanics and Microengineering. - Bristol : Institute of Physics Publishing (IOPP). - 0960-1317 .- 1361-6439. ; 25:10
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Journal article (peer-reviewed)abstract
- This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires by fusing for plasma characterization in microplasma sources. Here, the resulting endpoints, formed by droplets on the ends of a fused wire, are intended to act as spherical Langmuir probes. For studying the fusing behavior, bond wires were wedge bonded over a 2 mm wide slit, to emulate the final application, and fused with different voltages and currents. For electrical isolation, a set of wires were coated with a 4 μm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing its dynamics. Four characteristic tip shapes were observed: spherical, folded, serpentine shaped and semi-spherical. The stub length leveled out at ~400 μm as the fusing power increased. The fusing of the coated wires required a higher power to yield a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and was fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the I–V characteristics of a plasma generated by the SSRR. In a voltage range between −60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes, and will be considered for further integration.
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| 2. |
- Persson, Anders, et al.
(author)
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Optogalvanic spectroscopy with microplasma sources – Current status and development towards lab on a chip
- 2016
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In: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 26:10
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Journal article (peer-reviewed)abstract
- Miniaturized optogalvanic spectroscopy (OGS) shows excellent prospects of becoming ahighly sensitive method for gas analysis in micro total analysis systems. Here, a status reporton the current development of microwave induced microplasma sources for OGS is presented,together with the first comparison of the sensitivity of the method to conventional single-passabsorption spectroscopy. The studied microplasma sources are stripline split-ring resonators(SSRRs), with typical ring radii between 3.5 and 6 mm and operation frequencies around2.6 GHz. A linear response (R2 = 0.9999), and a stability of more than 100 s are demonstratedwhen using the microplasma source as an optogalvanic detector. Additionally, saturationeffects at laser powers higher than 100 mW are observed, and the temporal response of theplasma to periodic laser perturbation with repletion rates between 20 Hz and 200 Hz arestudied. Finally, the potential of integrating additional functionality with the detector isdiscussed, with the particular focus on a pressure sensor and a miniaturized combustor toallow for studies of solid samples.
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| 3. |
- Sturesson, Peter, 1981-, et al.
(author)
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Ceramic Pressure Sensor for High Temperatures – Investigation of the Effect of Metallizationon on Read Range
- 2017
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In: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 17:8, s. 2411-2421
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Journal article (peer-reviewed)abstract
- A study on the relationship between circuit metallization, made by double-layer screen printing of platinum and electroplating of silver on top of platinum, and its impact on practical read range of ceramic LC resonators for high-temperature pressure measurements is presented. Also included is the first realization of membranes by draping a graphite insert with ceramic green body sheets. As a quality factor circuit reference, two-port microstrip meander devices were positively evaluated and to study interdiffusion between silver and platinum, test samples were annealed at 500 degrees C, 700 degrees C, and 900 degrees C for 4, 36, 72, and 96 h. The LC resonators were fabricated with both metallization methods, and the practical read range at room temperature was evaluated. Pressure-sensitive membranes were characterized for pressures up to 2.5 bar at room temperature, 500 degrees C and up to 900 degrees C. Samples electroplated with silver exhibited performance equal to or better than double-layer platinum samples for up to 60 h at 500 degrees C, 20 h at 700 degrees C, and for 1 h at 900 degrees C, which was correlated with the degree of interdiffusion as determined from cross-sectional analysis. The LC resonator samples with double-layer platinum exhibited a read range of 61 mm, and the samples with platinum and silver exhibited a read range of 59 mm. The lowest sheet resistance, and, thereby, the highest read range of 86 mm, was obtained with a silver electroplated LC resonator sample after 36 h of annealing at 500 degrees C.
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