The present invention is a method for adjusting different resonant frequencies of a plurality of mechanical resonators formed on a common substrate, in a case where the resonant frequencies of the resonators are a function of each
resonator thickness. According to this method the resonators are each formed with an etchable top
electrode layer which includes a material having different
etching properties as a topmost layer for each of the resonators having different resonant frequencies. By selectively
etching these etchable
layers one at a time in the presence of the others, one may adjust the resonant frequencies of each of the resonators without need to
mask the resonators during the
etching process. Associated with this method there is a
resonator structure having a top
electrode structure having a topmost layer having different etching characteristics for different resonators.