Design and fabrication of high sensitivity nanomechanical resonant gas sensors using nanosphere lithography

Abstract

Gas detection systems are used in various fields such as environmental monitoring, medical and health care, and industries. In particular, miniaturized and accurate Micromachined Electrical Mechanical System (MEMS) gas sensors have been developed to apply the sensor to such various field. Among MEMS gas sensors, Capacitive Micromachined Ultrasonic Transducer (CMUT) which senses gas by direct mass detection methods has advantages such as higher quality factors. In this paper, a design to improve the mass sensitivity of CMUT is considered, and validate the device performance through the simulation. A CNUT device with a diameter of fewer than several microns has been proposed to improve sensitivity, however it is expensive to manufacture using conventional photolithography techniques. Therefore, we develop a new process by introducing nanosphere lithography processs to fabricate the designed CNUT devices. It is possible to fabricate the CNUT of radius less than sub-micron with low cost.