Role of SiO2 Layers in Third-Order Nonlinear Effects of Temperature Compensated BAW Resonators

This work applies a comprehensive nonlinear characterization process of two Temperature Compensated Bulk Acoustic Wave (TC-BAW) resonators. In both resonators, the SiO₂ layers have a remarkable impact on the generation of third- order intermodulation products (IMD3), confirming the impact of the SiO₂ on the generation of passive intermodulation. A unified model considering the electro-thermo-mechanical constitutive relations of the piezoelectricity is used, that allows to discern on the origin of the IMD3, either it comes from intrinsic nonlinearities of the materials, or from self-heating mechanisms.