Design, Modeling, and Characterization of a Novel Circular Surface Acoustic Wave Device

The design, modeling, and fabrication of a novel circular surface acoustic wave (SAW) device in complementary metal oxide semiconductor (CMOS) are introduced. The results obtained in authors´ previous work demonstrated that it is possible to design and fabricate SAW-based sensors in CMOS with comparable performances to conventional devices. It is of great interest to improve the transfer characteristics and to reduce the losses of conventional rectangular SAW architectures for obtaining highly selective sensor platforms. Performance deficiencies of regular SAW devices in CMOS were addressed with this new architecture for improved performance. A 3-D model for the novel architecture was constructed. A detailed finite-element analysis was carried out to examine the transient, harmonic, and modal behavior of the new architecture under excitation. The devices were fabricated in 0.5 mum AMI semiconductor technology and the postprocessing was carried out using cost-effective CMOS compatible methods. The results demonstrate that it is possible to obtain highly oriented SAWs by using the novel circular architecture. A 12.24 dB insertion loss improvement was achieved when compared with a conventional rectangular device that was fabricated in the same technology.