Integrated CMOS surface acoustic wave gas sensor: Design and characteristics

The development of inexpensive and miniaturized Surface Acoustics Wave (SAW) gas sensors that are highly selective and sensitive is described. These sensors are implemented with micro-electro-mechanical systems (MEMS) in CMOS technology. IDT equivalent circuit and model for SAW delay line is introduced. Simulation results are included for characterization and design of the sensor. In this paper we will describe the design and post-processing steps to implement SAW device in CMOS technology. Design parameters of this device were obtained using modeling equivalent circuit to characterize sensor. Two approaches were used in the design of the SAW gas sensor that will be discussed. A CMOS chip was fabricated using MOSIS. Thin film ZnO was grown on Silicon based die and its characterizations is presented.