Micromechanical device and related methods

A piezoelectric MEMS resonator comprising:

• a first layer comprising molybdenum;
• a second layer disposed above the first layer, the second layer comprising an aluminum nitride piezoelectric layer;
• a set of molybdenum electrodes disposed above the second layer, wherein the set of molybdenum electrodes comprises a set of interdigitated molybdenum electrodes;
• a silicon dioxide structure, wherein the first layer is disposed above the silicon dioxide structure;
• and
• a silicon layer, wherein the silicon dioxide structure is disposed above the silicon layer.