A MICROMACHINED CHEMICAL SENSOR FOR SEA FLOOR ENVIRONMENTS: INITIAL RESULTS

T. Li, K. Ding, W.E. Seyfried Jr, Y.B. Gianchandani
2012 2012 Solid-State, Actuators, and Microsystems Workshop Technical Digest   unpublished
This paper reports a micromachined chemical sensor intended for harsh environments such as those near hydrothermal vents at the sea floor. The sensor is intended to measure the pH, dissolved H 2 and H 2 S, and temperature. The device is 12 mm in diameter and 6 mm in effective length, including packaging. A YSZ|HgO|Hg solid electrode is used as a common electrode for measurement of the three chemical quantities. The YSZ diaphragm used for this electrode is <500 µm thick, allowing sufficient ion
more » ... onductance at temperatures >35°C. The other electrodes are thin-film metal electrodes fabricated on the same YSZ diaphragm: an Ag|AgCl reference electrode for pH sensing, an Ag|Ag 2 S electrode for H 2 S sensing, and a Pt electrode for H 2 sensing. The two temperature sensors are thin film Pt resistors. Initial tests have been performed to test the functionality of the pH and H 2 S sensors; measurements are in line with expectations.
doi:10.31438/trf.hh2012.46 fatcat:qtya2tra7rddhjmtnpcgoecxhi