Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silion nitride tubes

Tiggelaar, R.M. and Berenschot, J.W. and Boer de, J.H. and Sanders, R.G.P. and Gardeniers, J.G.E. and Oosterbroek, R.E. and Berg van den, A. and Elwenspoek, M.C. (2005) Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silion nitride tubes. Lab on a Chip, 5 (3). pp. 325-336. ISSN 1473-0197

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Abstract:	In this paper the fabrication and electrical characterization of a silicon microreactor for high-temperature catalytic gas phase reactions, like Rh-catalyzed catalytic partial oxidation of methane into synthesis gas, is presented. The microreactor, realized with micromachining technologies, contains silicon nitride tubes that are suspended in a flow channel. These tubes contain metal thin films that heat the gas mixture in the channel and sense its temperature. The metal patterns are defined by using the channel geometry as a shadow mask. Furthermore, a new method to obtain Pt thin films with good adhesive properties, also at elevated temperatures, without adhesion metal is implemented in the fabrication process. Based on different experiments, it is concluded that the electrical behaviour at high temperatures of Pt thin films without adhesion layer is better than that of Pt/Ta films. Furthermore, it is found that the temperature coefficient of resistance (TCR) and the resistivity of the thin films are stable for up to tens of hours when the temperature-range during operation of the microreactor is below the so-called burn-in temperature. Experiments showed that the presented suspended-tube microreactors with heaters and temperature sensors of Pt thin films can be operated safely and in a stable way at temperatures up to 700 °C for over 20 h. This type of microreactor solves the electrical breakdown problem that was previously reported by us in flat-membrane microreactors that were operated at temperatures above 600 °C.
Item Type:	Article
Copyright:	© Royal Society of Chemistry 2005
Faculty:	Science and Technology (TNW) Electrical Engineering, Mathematics and Computer Science (EEMCS)
Research Group:	Mesoscale Chemical Systems (MCS) Biomedical and Environmental Sensor systems (BIOS) Transducers Science and Technology (TST)
Link to this item:	http://purl.utwente.nl/publications/50950
Official URL:	http://dx.doi.org/10.1039/b414857f
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