Reduction of TCF effect in FBAR devices using DC bias

Abstract

This study investigates the effect of applied DC bias on the resonant and antiresonant frequency of FBAR devices. In our model, we introduce linear electrostrictive coefficients and compare the theoretical results with experimental data. The FBAR structure utilizes an air cavity as the acoustic reflector layer, with Mo and AlN as the materials for the top/bottom electrodes and the piezoelectric layer, respectively. The resonant and antiresonant frequencies of the FBAR are designed at 2313.1 and 2374.7 MHz, respectively. Under an applied DC bias ranging from −10 to +10 V, the frequency shifts for the resonant and antiresonant frequencies are 37.7 and 27.7 ppm/V, respectively. The theoretical results, incorporating linear electrostrictive coefficients N=−7×1010 and G=−5×109, show excellent agreement with the measured results of the FBAR device. Finally, we compensated for the frequency drift by applying a 20 V DC bias at high temperatures to the FBAR device. These findings have significant implications for improving the performance of RF communication systems in varying temperature environments.