MEMS resonators
AssigneeNXP B.V.
InventorRobert James Pascoe Lander
Life of this patent
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Abstract
A crystalline semiconductor resonator device comprises two matched resonators which are aligned differently with respect to the crystal structure of the crystalline semiconductor. The resonators each comprise a portion of a material having a different temperature dependency of the Young's modulus to the temperature dependency of the Young's modulus of the crystalline semiconductor material. In this way, the suspension springs for the resonators have different properties, which influence the resonant frequency. The resonant frequency ratios between the first and second resonators at a calibration temperature and an operation temperature are measured. A frequency of one (or both) of the resonators at the operation temperature can then be derived which takes into account the temperature dependency of the one of the resonators.
Claims20
A crystalline semiconductor resonator device comprising:
- a first resonator having an elongate spring member which includes a first portion of a crystalline semiconductor, for supporting a semiconductor resonator mass of the first resonator;
- a second resonator having an elongate spring member which includes a second portion of the crystalline semiconductor for supporting a resonator mass of the second resonator,
- wherein the elongate spring members are aligned with respect to a crystal structure of the crystalline semiconductor such that the respective elongate spring members have Young's moduli that are different from one another,
- wherein the elongate spring members of the first and second resonators each include a portion of a material having a temperature dependency of the Young's modulus that is different than a temperature dependency of the Young's modulus of the crystalline semiconductor;
- and
- a measurement device for measuring a resonant frequency ratio between the first and second resonators at a calibration temperature and an operation temperature and for deriving therefrom a frequency of one of the resonators at the operation temperature which takes into account the temperature dependency of the one of the resonators.
A method of operating a crystalline semiconductor resonator, comprising:
- measuring a resonant frequency ratio between first and second resonators at a calibration temperature (T0), each resonator including an elongate spring member having a crystalline semiconductor, the elongate spring members being aligned differently with respect to a crystal structure of the crystalline semiconductor such that each elongate spring member has a Young's modulus that is different than a Young's modulus of the other elongate spring member, and the elongate spring members of the first and second resonators each including a portion of a material having a temperature dependency of the Young's modulus that is different than a temperature dependency of a Young's modulus of the crystalline semiconductor;
- measuring the resonant frequency ratio between first and second resonators at an operation temperature;
- and
- deriving, from the resonant frequency ratios measured at the calibration temperature and at the operation temperature, a frequency of one of the resonators at the operation temperature which takes into account the temperature dependency of the one of the resonators.
Dependencies are inferred from the claim text.