Power Durability Enhancement of Surface Acoustic Wave Filter with Multilayer Electrodes

The rapid development of mobile communication puts higher requirements on performance of surface acoustic wave(SAW) filters.With the enhancement of input power and scale miniaturization, the power density of SAW device increases sharply.Acoustomigration of Al interdigital transducers(IDT) electrodes occurs at high power density results in device failure, and thus how to make the device work stably at high power has become a key scientific issue in SAW industry.Aiming at the difficulty of poor anti-acoustomigration ability of Al electrode, the finite element method was used to calculate the stress distribution and reveal the weakest part.According to the stress distribution, multilayer electrode Al-0.9 wt.%Cu(Al-Cu)/Ti/Cu/Ti was designed and prepared, which is desirable to improve the power durability of the device.X-ray diffraction, atomic force microscopy, transmission electron microscopy were used to characterize the texture and microstructure of the IDT electrodes, and revealed the influence of the electrode microstructure state on the power durability of the SAW filter.The power test demonstrated that the power durability of SAW filter with multilayer electrode reaches 34.5 dBm(2.81 W), which is 1.78 times that of the Al-Cu/Ti electrode.This work provides a low cost and easy preparation electrode solution for high power durable SAW devices in the 5G era.