Microelectromechanical resonant structure having improved electrical characteristics
First Claim
1. A MEMS resonant structure, comprising:
- a substrate of semiconductor material having a top surface;
a plurality of constraint elements configured to be compliant in a vertical direction;
a mobile mass suspended above said substrate and anchored to said substrate by the plurality of constraint elements, the mobile mass having a planar extension that is configured to move substantially uniformly as a whole, the mobile mass being configured to oscillate at a resonance frequency; and
a fixed-electrode structure capacitively coupled to said mobile mass to form a capacitor with a capacitance that varies as a function of the oscillation of said mobile mass, said fixed-electrode structure being positioned on the top surface of said substrate, and said constraint elements being configured to expand and contract to enable the mobile mass to oscillate substantially uniformly in the vertical direction, transverse to said top surface of said substrate.
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Abstract
The present disclosure is directed to a MEMS resonant structure, provided with a substrate of semiconductor material; a mobile mass suspended above the substrate and anchored to the substrate by constraint elements to be free to oscillate at a resonance frequency; and a fixed-electrode structure capacitively coupled to the mobile mass to form a capacitor with a capacitance that varies as a function of the oscillation of the mobile mass; the fixed-electrode structure arranged on a top surface of the substrate, and the constraint elements being configured in such a way that the mobile mass oscillates, in use, in a vertical direction, transverse to the top surface of the substrate, keeping substantially parallel to the top surface.
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Citations
28 Claims
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1. A MEMS resonant structure, comprising:
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a substrate of semiconductor material having a top surface; a plurality of constraint elements configured to be compliant in a vertical direction; a mobile mass suspended above said substrate and anchored to said substrate by the plurality of constraint elements, the mobile mass having a planar extension that is configured to move substantially uniformly as a whole, the mobile mass being configured to oscillate at a resonance frequency; and a fixed-electrode structure capacitively coupled to said mobile mass to form a capacitor with a capacitance that varies as a function of the oscillation of said mobile mass, said fixed-electrode structure being positioned on the top surface of said substrate, and said constraint elements being configured to expand and contract to enable the mobile mass to oscillate substantially uniformly in the vertical direction, transverse to said top surface of said substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An oscillator circuit, comprising:
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a MEMS resonant structure, including; a substrate of semiconductor material having a top surface; a plurality of constraint elements configured to expand and contract in a vertical direction that is transverse to the top surface of the substrate; a mobile mass suspended above said substrate and anchored to said substrate by the plurality of constraint elements, the mobile mass having a planar extension that is configured to move substantially uniformly as a whole, the mobile mass being configured to oscillate at a resonance frequency; and a fixed-electrode structure capacitively coupled to said mobile mass to form a capacitor with a capacitance that varies as a function of the oscillation of said mobile mass, said fixed-electrode structure being positioned on the top surface of said substrate, and said constraint elements being configured to enable the mobile mass to oscillate substantially uniformly in the vertical direction; and a biasing stage configured to bias said mobile mass and said fixed-electrode structure. - View Dependent Claims (18, 19, 20)
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21. A method, comprising:
forming a MEMS resonant structure, the forming including; forming a fixed-electrode structure on a top surface of a substrate; forming a mobile mass capacitively coupled to the fixed-electrode structure, the mobile mass being configured to substantially uniformly oscillate at a resonance frequency, the mobile mass having a main extension that is substantially uniformly spaced from the top surface of the substrate in a resting state; and forming a plurality of constraint elements coupled to the mobile mass, the constraint elements being configured to anchor the mobile mass to the substrate and to expand and contract in a vertical direction to enable the mobile mass to oscillate in the vertical direction transverse to the top surface of the substrate, the main extension as a whole being configured to be substantially uniformly spaced from the top surface of the substrate as the mobile mass oscillates. - View Dependent Claims (22, 23, 24)
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25. A MEMS resonant structure, comprising:
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a substrate of semiconductor material having a top surface; a plurality of constraint elements; a mobile mass suspended above the substrate and anchored to the substrate by the plurality of constraint elements, the mobile mass being configured to oscillate at a resonance frequency; a fixed-electrode structure capacitively coupled to the mobile mass to form a capacitor with a capacitance that varies as a function of the oscillation of the mobile mass, the fixed-electrode structure being positioned on the top surface of the substrate, and the constraint elements being configured to enable the mobile mass to oscillate in a vertical direction, transverse to the top surface of the substrate, the fixed-electrode structure including; an actuation electrode positioned on the top surface of the substrate underneath the mobile mass; regulation electrodes being positioned on the top surface of the substrate and capacitively coupled to the mobile mass, the regulation electrodes being positioned laterally with respect to the actuation electrode, at least partially underneath the mobile mass, the regulation electrodes being configured to receive a regulation voltage to vary an electrostatic force acting on the mobile mass to change the resonance frequency. - View Dependent Claims (26, 27, 28)
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Specification