MEMS resonator structure and method

A microelectromechanical resonator comprising:

• a resonator mass that oscillates in a bulk mode, the oscillation including a first state in which the resonator mass is contracted, at least in part, in at least one of a first direction and a second direction, and wherein in the first state, the resonator mass is expanded, at least in part, in at least one of a third direction and a fourth direction, the second direction being opposite the first direction, the fourth direction being opposite the third direction, wherein the resonator mass includes:
• a first plurality of regions each having a density;
• and
• a second plurality of regions each having a density, wherein the density of each of the second plurality of regions is different than the density of each of the first plurality of regions;
• and
• wherein the second plurality of regions are disposed in a non uniform arrangement.