A novel approach of thermal excitation is presented, where thin micromechanical structures are suspended by deep-diffusion bases. Cantilevers and microbridges are fabricated, modeled and tested. Resonance frequencies are solely determined by the thin parts of the structures, and are independent of material properties and dimensions of the base. The efficiency for the amplitude of vibration is independent of the thickness and length of the base. Therefore short and thick bases can be applied, leading to relatively small temperature elevations inherent to thermal excitation.