VOC Detection by MEMS Sensor with Readout Circuit

Breath-based volatile organic compound (VOC) sensors are important for developing a non-invasive way of disease detection. Currently used blood-based devices for the detection of disease are invasive and cause discomfort to the patient. This paper reports a non-invasive and sensitive method of disease detection which depends on thermal actuation in a MEMS device and the capacitive readout circuit of the sensor which is verified in proteus software. The sensor design simulation, static and modal analysis to study the top plate displacement and the device's vibration frequency is done using CoventorWare software. The simulation study depicts a linear response by the sensor for a wide range of VOC concentrations with a sensitivity of .54 mu m/Pa. The relation of sensor response with various other parameters like sensing layer thickness, length and width of the beam, perforation size of the top layer, distance between top and bottom layer, the temperature profile of the micro heater, etc. are also described. It is observed that the top plate supported by four beams is more sensitive to applied load as compared to ring-supported. By functionalization of the sensing layer, this device can be extremely useful in the detection of specific diseases using breath biomarkers, as the tool for sensing, in point-of-care applications.