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Comparisons between Membrane, Bridge and Cantilever Miniaturized Resistive Vacuum Gauges

Using bulk micromachining, meander-shaped resistor elements consisting of 20 nm Cr and 200 nm Au were fabricated on 1 μm thick silicon nitride membranes, bridges, and cantilevers. The resistance change as a function of pressure depends strongly on the thermal resistance of the two metal lines connec...

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Detalles Bibliográficos
Autores principales: Punchihewa, Kasun Gardiye, Zaker, Evan, Kuljic, Rade, Banerjee, Koushik, Dankovic, Tatjana, Feinerman, Alan, Busta, Heinz
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Molecular Diversity Preservation International (MDPI) 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444074/
https://www.ncbi.nlm.nih.gov/pubmed/23012516
http://dx.doi.org/10.3390/s120708770
Descripción
Sumario:Using bulk micromachining, meander-shaped resistor elements consisting of 20 nm Cr and 200 nm Au were fabricated on 1 μm thick silicon nitride membranes, bridges, and cantilevers. The resistance change as a function of pressure depends strongly on the thermal resistance of the two metal lines connecting the heated resistor to the silicon bulk (cold junction) and on the thermal resistance of the silicon nitride. Relative resistance changes ranging from about 3% (small membrane) to 20% (bridge) per mW of input power were obtained when operating the devices in constant voltage mode. The pressure where maximum sensitivity of these gauges occurs depends on the distance ‘d’ between the periphery of the heated resistor element and the silicon cold junction. Devices with ‘d’ ranging from 50 μm to 1,200 μm were fabricated. Assuming that pressures can be reliably measured above the 10% and below the 90% points of the resistance versus pressure curve, the range of these devices is about two orders of magnitude. By integrating two devices, one with d = 65 μm and one with d = 1,200 μm on the same chip and connecting them in series, the range can be increased by about a factor of three. By fabricating the cantilever devices so that they curl upon release, it will be shown that these devices also exhibit larger range due to varying ‘d’.