Research Progress in Filter Design and Fabrication Technology

Dr. Yao CAI

Associate Professor, Wuhan University    

Abstract:

As a core component in 5G communication systems, radio frequency (RF) filters face multiple challenges under high-frequency and broadband development requirements: resistive losses in thin electrodes, stress/crystallographic orientation control bottlenecks in high-Sc-doped AlN thin films, lack of material parameters and simulation models, as well as moisture permeation and mechanical stress issues in packaging. The research team at Wuhan University has significantly enhanced the preferred crystal orientation of piezoelectric AlN/ScAlN films by optimizing seed layer/buffer layer deposition processes; proposed innovative resonator structures based on piezoelectric theory and acoustic-electromagnetic multiphysics co-simulation methodologies; and concurrently developed chip-level/wafer-level packaging technologies to effectively address stress matching and reliability challenges. These achievements provide a comprehensive material-design-packaging solution for domestically produced high-performance filters, supporting the strategic need for 5G/6G RF front-end autonomy.

Speaker's Biography:

Yao CAI, Associate Professor at Wuhan University, specializing in piezoelectric materials design, device fabrication, and RF filter research. Focusing on the mechanistic investigation of ScAlN thin films, he has successfully resolved residual stress control challenges and developed high-frequency, large-bandwidth RF filter chips based on ScAlN thin films. As first/corresponding author, he has published over 20 research papers in the field of filters and secured 30+ granted invention patents covering core technologies such as heterostructure design and wafer-level packaging. He presides over projects supported by the National Natural Science Foundation of China and the Central Universities' Basic Research Fund, among others.