Design and fabrication of a novel SAW bio/chemical sensor in CMOS

The design, fabrication, post-processing and characterization of a novel SAW (Surface Acoustic Wave) based bio/chemical sensor in CMOS technology is introduced. The sensors are designed in AMI 1.5 mum 2 metal, 2 poly process. A unique maskless post processing sequence is designed and completed. The three post-processing steps are fully compatible with any CMOS technology. This allows any signal control/processing circuitry to be easily integrated on the same chip. ZnO is used as the piezoelectric material for the SAW generation. A thorough characterization and patterning optimization of the sputtered ZnO was carried out. The major novelties that are introduced in the SAW delay line features are: The embedded heater elements for temperature control, compensation and acoustic absorbers that are designed to eliminate edge reflections and minimize triple transit interference. Both of these attributes are designed by using the CMOS layers without disturbing the SAW performance