Vertical capacitive SiBARs

This work introduces high frequency, vertical silicon bulk acoustic resonators (SiBAR). A combination of the new resonator structures with much larger transduction area and the HARPSS fabrication process is used to demonstrate high frequency capacitive resonators with significantly lower impedances compared to the previous capacitive resonators. Impedances as low as a few kilo-Ohms and quality factors in the range of 20,000 to 50,000 in the VHF range have been achieved for the first thickness mode of the fabricated resonators. Resonant frequencies as high as 983MHz are demonstrated for the third thickness modes of the capacitive SiBARs.