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In this paper, we fabricated and evaluated a flowmeter with a sub-micron sized piezoresistive layer for the measurement in the small area. For the small area detection, the sensing material should be reduced as well as sensor body. We use the FIB system to reduce the size of the sensing material and obtain the sub-micron sized line width. The device is fabricated with the standard MEMS process, and the platinum layer is selected as the piezoresistive material considering the electrical conductivity. The 0∼4m/s air flows are applied to the flowmeter and the experimental results shows the negative sensitivity output with -3.22E−5/ms−1. This negative value is due to the additional materials like carbon and gallium. The various experiments including stability and repeatability are performed, and the repeated operation shows stable output signals with less than 9.6% variation. Through those experiment results, the FIB assisted platinum layer is suitable for the piezoresistive detection and a flowmeter can be applied to measurement of flow rate in the small area. [ABSTRACT FROM AUTHOR]

We fabricated and evaluated a flowmeter with a corrugation structure for various applications. The device measures the air flow rate using the air drag force, and the corrugation structure is adopted for the more deformation which brings the higher sensitivity. The flowmeter is fabricated with standard CMOS process, and the strain is measured with the piezoresistive material, platinum. The fabricated flowmeter measures the small air flow rate to 0.2 m/s and has a wide measurement range up to 7 m/s. The stability and repeatability characteristics are investigated, and around 5% uniform results are obtained. The flowmeter is used for the 2-dimensional measurement, and the air flow rate and direction are determined with the compensated vector calculation. [ABSTRACT FROM PUBLISHER]

Abstract: We designed, fabricated and evaluate the novel air flowmeter with corrugation structure for the detection of low air velocity. For measuring the low air flow rate, the sensitivity related factors, the air drag force and the output signal, should be improved at the given air flow. The device has the paddle structure, and the maximized air drag force is obtained with vertical air flow. The output signal is also improved with the corrugation structure and measured with piezoresistive detection. The low air flow rate with less than 1m/s air velocity are applied, and the fabricated flowmeter with corrugation structure shows the better sensitivity and the response time than those of flat one. Various experiments about repeated measurements also show the stabilized signals. [Copyright &y& Elsevier]