Mechanistic investigation of annealing-induced power capacity enhancement in aluminum nitride bulk acoustic wave resonators

YQ Ren and C Gao and HY Li and X Chen and YP Zheng and Y Liu and QW Xu and Y Cai and CL Sun, PHYSICA SCRIPTA, 100, 095908 (2025).

DOI: 10.1088/1402-4896/adfe42

The rapid development of mobile communication continues to drive thin- film bulk acoustic resonators (FBARs) towards higher power capacity. Aluminum nitride (AlN) is widely utilized in FBARs as the core functional material. However, the crystal defects in sputtered aluminum nitride (AlN) thin films significantly degrade their physical properties, affecting the devices' power capacity. This study used a multiscale research methodology to achieve an integrated approach combining atomic-level simulation with device-level performance analysis. Based on molecular dynamics simulations, the micro-mechanism of lattice evolution during thermal annealing was revealed. The temperature-dependent evolution of the hexagonal lattice fraction, radial distribution function, and thermal conductivity was quantitatively characterized. After incorporating the simulated thermal conductivity enhancement effect into the finite element model, the thermal behavior of the device was effectively predicted. The results show that appropriate temperature annealing significantly improves the crystal quality and thermal conductivity of AlN, thereby reducing the heat generation of FBARs under the same power. The method of using annealing to increase the power capacity of FBARs is thus proposed, and the test results show that annealing FBARs at 500 degrees C increases the power capacity from +29.6 dBm (without annealing) to +30.8 dBm.

Return to Publications page