Comparisons between membrane, bridge and cantilever miniaturized resistive vacuum gauges
| Autor: | Heinz H. Busta, Evan Zaker, Kasun Punchihewa, Koushik Banerjee, Tatjana Dankovic, Rade Kuljic, Alan Feinerman |
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| Rok vydání: | 2012 |
| Předmět: |
low power sensing
Bulk micromachining Materials science Cantilever Silicon air Thermal resistance chemistry.chemical_element Nanotechnology lcsh:Chemical technology Biochemistry Article Analytical Chemistry law.invention chemistry.chemical_compound silicon bulk micromachining law lcsh:TP1-1185 MEMS-based Pirani gauges miniaturized vacuum and pressure gauges Electrical and Electronic Engineering Instrumentation Resistive touchscreen business.industry Atomic and Molecular Physics and Optics Silicon nitride chemistry Optoelectronics thermal conductivity of metals insulators Resistor business Order of magnitude |
| Zdroj: | Sensors (Basel, Switzerland) Sensors Volume 12 Issue 7 Pages 8770-8781 Sensors, Vol 12, Iss 7, Pp 8770-8781 (2012) |
| ISSN: | 1424-8220 |
| Popis: | 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’. |
| Databáze: | OpenAIRE |
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