Micro-electromechanical acoustic resonators include a resonator body suspended over a substrate. The resonator body may have a single perforation therein, which may extend substantially or completely therethrough. The resonator body may also be configured to have a center-of-mass within an interior of the perforation and/or a nodal line that overlaps the perforation. A perimeter and depth of the single perforation can be configured to reduce a susceptibility of the acoustic resonator to process-induced variations in resonant frequency relative to an otherwise equivalent resonator that omits the single perforation. In other embodiments, the resonator body may have multiple perforations therein that extend along a nodal line of the resonator.