Micromechanical resonator and method for manufacturing thereof
AssigneeTeknologian tutkimuskeskus VTT Oy
InventorsAntti Jaakkola, Tuomas Pensala
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Abstract
The invention relates to a temperature compensated micromechanical resonator and method of manufacturing thereof. The resonator comprises a resonator element comprising a semiconductor crystal structure, which is doped so as to reduce its temperature coefficient of frequency, transducer means for exciting to the resonator element a vibrational mode. According to the invention the crystal orientation and shape of the resonator element are chosen to allow for a shear mode having a saddle point to be excited to the resonator element, and said transducer means are adapted to excite said shear mode to the resonator element. Accurate micromechanical resonators with now temperature drift can be achieved by means of the invention.
Claims18
A temperature compensated micromechanical resonator comprising
- a resonator element comprising a semiconductor crystal structure, which is doped so as to reduce its temperature coefficient of frequency, and
- transducer means for exciting to the resonator element a vibrational mode, wherein
- the crystal orientation and shape of the resonator element are chosen to allow for a shear mode having a saddle point to be excited to the resonator element, and
- said transducer means are adapted to excite said shear mode to the resonator element, wherein the transducer means comprises at least one piezoactive zone on the resonator element and adapted to subject a flexural perpendicular to the plane of the resonator element to the resonator element.
Method of manufacturing a passively temperature-compensated micromechanical resonator, comprising
- providing a semiconductor wafer having a doped device layer,
- forming a resonator element from said device layer, and
- providing transducer means capable of exciting a vibrational mode to the resonator element, wherein the crystal orientation of the semiconductor wafer and shape of the resonator element are chosen allow a shear mode having a saddle point as said vibrational mode, and wherein the transducer means comprises at least one piezoactive zone on the resonator element and adapted to subject a flexural perpendicular to the plane of the resonator element to the resonator element.
Dependencies are inferred from the claim text.