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US 7,071,793 B2Granted
Temperature compensation for silicon MEMS resonator
AssigneeRobert Bosch GmbH
InventorsMarkus Lutz, Aaron Partridge
Life of this patent
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Abstract
Thermally induced frequency variations in a micromechanical resonator are actively or passively mitigated by application of a compensating stiffness, or a compressive/tensile strain. Various composition materials may be selected according to their thermal expansion coefficient and used to form resonator components on a substrate. When exposed to temperature variations, the relative expansion of these composition materials creates a compensating stiffness, or a compressive/tensile strain.
Claims19
A micromechanical resonator, comprising:
- a substrate formed from a first material having a first thermal expansion coefficient;
- a beam suspended above the substrate and formed from a plurality of materials which, in combination, provide a second thermal expansion coefficient;
- and
- an anchor structure, coupled to the beam, to suspend the beam above the substrate, wherein the anchor structure is formed from a plurality of materials which, in combination, provide a third thermal expansion coefficient and wherein the third thermal expansion coefficient is different from the second thermal expansion coefficient.
1 more element
A micromechanical resonator, comprising:
- a substrate formed from a first material having a first thermal expansion coefficient;
- a beam formed from a second and third materials which, in combination, provide a second thermal expansion coefficient which is different from the first thermal expansion coefficient, wherein the beam is suspended above the substrate by at least one anchor structure;
- wherein the at least one anchor structure is formed from a plurality of materials which, in combination, provide a third thermal expansion coefficient which is different from the second thermal expansion coefficient.
A micromechanical resonator, comprising:
- a substrate formed from a first material having a first thermal expansion coefficient;
- an oscillating beam formed from an active layer deposited over the substrate, wherein the active layer is formed from:
- (1) a second material having a second thermal expansion coefficient which is different from the first thermal expansion coefficient and (2) a third material having a third thermal expansion coefficient which is different from the second thermal expansion coefficient;
- a first anchor structure which is formed, at least in part, from a fourth material having a fourth thermal expansion coefficient, and wherein the fourth thermal expansion coefficient is different from the second and third thermal expansion coefficients;
- and
- wherein the first anchor structure is disposed on the substrate to, at least in part, support the oscillating beam above the substrate.
3 more elements
Dependencies are inferred from the claim text.