Etch-hole-assisted energy dispersion for enhancing quality factor in silicon bulk acoustic resonators

This paper empirically demonstrates how the quality factor (Q) of a width-extensional mode single-crystal silicon bulk-acoustic-resonator (SiBAR) can be enhanced by three times by strategic placement of holes on the structure. The holes serve to disperse the strain energy field concentrated primarily around the nodal lines, ultimately re-distributing strain energy away from the anchors. This in turn reduces anchor loss and thus enhances Q. These results agree well with our finite-element (FE) simulations. We envisage that the concepts reported herein can be extended to even higher performance resonators like piezoelectric aluminum nitride contour mode resonators.