Miniaturized multi-sensor for aquatic studies

Karen Birkelund, Anders Hyldgård, Dennis Mortensen, Erik Vilain Thomsen

    Research output: Contribution to journalJournal articleResearchpeer-review


    We have developed and fabricated a multi-sensor chip for fisheries’ research and demonstrated the functionality under controlled conditions. The outer dimensions of the sensor chip are 3.0 × 7.4 × 0.8 mm3 and both sides of the chip are utilized for sensors. Hereby a more compact chip is achieved that allows for direct exposure to the seawater and thereby more accurate measurements. The chip contains a piezo-resistive pressure sensor, a pn-junction photodiode sensitive to visible light, a four-terminal platinum resistor for temperature measurement and four conductivity electrodes for the determination of the salinity of saltwater. Pressure, light intensity, temperature and salinity are all essential parameters when mapping the migration route of fish. The pressure sensor has a sensitivity of S = 1.44 × 10−7 Pa−1 and is optimized to 20 bar pressure; the light sensor has a quantum efficiency between 52% and 74% in the range of visible light. The temperature sensor responds linearly with temperature and has a temperature coefficient of resistance of 2.9 × 10−3 K−1. The conductivity sensor can measure the salinity with an accuracy of ±0.1 psu. This is all together the smallest and best functioning fully integrated MEMS-based multi-sensor made to date for this specific application. However, each single-sensor performance can be optimized by introducing a considerably more complicated process sequence. In this paper, a new simpler process for integrating the four sensors on one single chip is presented in details for the first time. Further, an optimized performance of the individual sensors is presented.
    Original languageEnglish
    JournalMeasurement Science and Technology
    Pages (from-to)055802
    Publication statusPublished - 2011


    • Data storage tags
    • Conductivity
    • Temperature
    • Quantum efficiency
    • Sensors for fish
    • Aquatic studies
    • Salinity
    • Sensor
    • Marine studies
    • Photodiode
    • Multi-MEMS-sensor
    • Light
    • Pressure
    • DST


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