Dissolved Oxygen MEMS Sensor With Enhanced Sensing Current

A new approach is proposed to enhance sensing amperometric current in three-electrode Clark dissolved oxygen (DO2) Microelectromechanical systems (MEMS) sensors. In the proposed approach, the counter electrode (CE) in a conventional concentric three-electrode sensor is modified to admit a large ratio of static electric current in an electrochemical solution. The typically large CE of a conventional sensor is replaced with an array of narrow-width electrodes. The modified CE is expected to reduce the inductive coupling and simultaneously increase the capacitive coupling of the structure. The overall changes of inductive and capacitive couplings are shown to enhance the sensing amperometric current of the sensor. Two μ-sensors are developed and fabricated based on MEMS technology including a conventional, as the reference and a new modified μ-sensors. The experimental results confirm an enhancement of 3.2:1 (0.352 μA:0.112 μA for 23% of DO2) in the sensing amperometric current of the developed MEMS μ-sensor compared to the conventional same-sized counterpart.