Design and Optimization of a Multichannel Quartz Crystal Microbalance Sensor Array for Multiple Target Gas Detection

Quartz Crystal Microbalance is a candidate technology for high sensitivity gas detection that operates based on the thickness shear mode of piezoelectric crystal. These sensors can detect nanogram level of mass change on their electrode surface, which leads to a high accuracy of detection while benefiting from a simple geometry, low cost and ease of fabrication. Unlike conventional Quartz Crystal Microbalance sensors that are limited to a single-electrode structure hampering their detection capability, in this work a novel 5MHz multielectrode sensor is designed and optimized on a single substrate. This developed sensor can be used for detection of simultaneously present multiple gases in a complex environment. Therefore, this new design configuration eliminates the need for multiple sensors and reduces the complexity of fabrication and measurements. In order to enhance the proposed device's performance, analytical modeling and finite element analysis are further conducted to optimize the device structure for highsensitivity applications. A four-electrode 5MHz sensor configuration is developed on a single substrate with the optimized electrodes' thickness, radius, and center to center distance of 300nm, 500μm, and 6.5mm respectively. The sensor achieved a high sensitivity of 0.135 Hz.cm
²
.ng
^-1
while eliminating the interference between the electrodes.