Abstract
This report presents a novel method to obtain BAW resonators with different resonant frequencies on the same substrate without additional tuning layer. The resonant frequency of each resonator is adjusted by forming numerous holes of dimensions smaller than the acoustic wavelength on the top electrode. Here we demonstrate that the resonant frequency can be adjusted, by controlling the area of the holes, within a range of 170 MHz on a BAW resonator with the resonant frequency of 1.9 GHz. The results indicate that BAW filters can be tuned by means of photolithographic patterns, and therefore the manufacturing cost is lower than a conventional BAW filter with additional tuning layer.
