Design and Fabrication of AlN SAW Resonators for Measuring Particulate Matter Characteristics

Abstract

In the rapidly advancing field of industrial technology, the demand for enhanced accuracy in environmental Particulate Matter (PM) monitoring has intensified. The Background Section explores the potential of Micro-Electro-Mechanical Systems (MEMS) technology in developing high-resolution, sensitive, and portable devices for PM mass and size detection. The Second and Third Sections provide an overview of the working principles of various acoustic devices and discuss both conventional and advanced PM sensing methodologies. The Piezoelectric Material Alternatives Section concludes with a comparative analysis of different piezoelectric materials.

Design parameters were determined through simulations, as discussed in Section Five, leading to the successful fabrication of a 95 MHz-412 MHz cross-structure SAW resonator in the TUDelft Else Kooi Laboratory cleanroom, detailed in the Fabrication Section. The change in resonant frequency of the device was measured using a Vector Network Analyzer (VNA) probe station, as outlined in the Measurement Results and Discussion Section. The results demonstrate that the device can effectively detect mass loading surface perturbations generated by a 40 μm diameter, 200 nm  high aluminium column in the detection region, despite its inability to sense actual 15 µm SiO2 particle clusters. Finally, the Reflection and Recommendations Section summarizes the project and offers suggestions for future development.