Fabrication and characterization of SAW IDT biosensor for biomolecule detection

Abstract

Surface Acoustic Wave (SAW) device uses piezoelectric effect to generate acoustic wave on the piezoelectric substrate by using Interdigital Transducers (IDT). Early application was in telecommunication field as filter and resonators. However, due its sensitivity to mass, viscosity and velocity changes on the path between two IDTs, it is used as biosensors. In this project, the focus will be on fabrication and characterization of the IDTs parameter of the SAW device using conventional photolithography and lift-off technique. Finger width, acoustic aperture and number of IDT finger pairs were varied to analyze its effect on the resistance, coupling capacitance, and frequency response. After the lift-off technique, the completed SAW devices were characterized with respect to its parameter for its current-voltage, capacitance-voltage and frequency response. SAW device with more IDT fingers, higher finger width and acoustic aperture produce lower lead resistance and higher capacitance.