A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

A dual-mode resonator, devices employing the dual-mode resonator, and the methods of making the resonator and the devices are disclosed. Embodiments include a dual-mode resonator including a semiconductor substrate; a material on the semiconductor substrate, having a cavity formed therein; a seed layer over the cavity in a V-shape, wherein sides of the V-shape form an angle of 15 to 25 degrees with a horizontal line; a bottom electrode on the seed layer; an acoustic layer on the bottom electrode; a top electrode on the acoustic layer; and a mass loading layer on the top electrode; and a cap over the dual-mode resonator.

A micromechanical resonator is provided that enables a smaller total package size with an acceptable quality factor for timing applications. The MEMS resonator includes a vibration portion with a base and three or more vibrating beams extending therefrom. Moreover, the MEMS resonator includes a frame that surrounds a periphery of the vibration portion and a pair of anchor between the vibrating beams for stabilizing the vibration portion within the frame. Furthermore, support beams couple the base of the vibration portion to the pair of anchors.

The present disclosure provides an aerosol sensing method. The aerosol sensing method includes steps of providing an entering process, providing a particle collecting process and providing a measuring process. The entering process is to allow an aerosol to enter a chamber of a thermal-piezoresistive oscillator-based aerosol sensor, and a thermal-piezoresistive resonator is disposed in the chamber. The particle collecting process is to allow particulate matters in the aerosol to land on at least one proof-mass of the thermal-piezoresistive resonator when the thermal-piezoresistive resonator is not driven. The measuring process is to use an electrical signal to drive the thermal-piezoresistive resonator and measure a resonant frequency of the thermal-piezoresistive resonator. The particle collecting process and the measuring process are operated in a repetitive cycle for measuring changes of the resonant frequency of the thermal-piezoresistive resonator to measure the particulate matters of the aerosol.

A MEMS resonator device includes: (i) a support structure, (ii) a resonator element doped with at least one of N-type or P-type dopants, wherein a doping concentration of the at least one of N-type or P-type dopants causes a closely temperature-compensated mode in which (a) an absolute value of a first order temperature coefficient of frequency of the resonator element is reduced to a first value below a threshold value and (b) an absolute value of a second order temperature coefficient of frequency of the resonator element is reduced to about zero, and wherein an anchor decoupler region formed on the resonator element causes the absolute value to be further reduced to a second value, and (iii) at least one anchor coupling the resonator element to the support structure, wherein the anchor decoupler region is formed on the resonator element at least partially surrounding the at least one anchor.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

A compound spring MEMS resonator includes a resonator body constructed using one or more spring unit cells forming a compound spring block and one or more compound spring blocks forming the resonator body. Each compound spring block is anchored at nodal points to ensure a high quality factor. The resonator body further includes masses attached to the open ends of the compound spring block and capacitively coupled to drive/sense electrodes. The dimensions of the spring unit cells, the number of spring unit cells for a compound spring block, the size and weight of the masses, and the length and width of the support beams are selected to realize a desired resonant frequency. Meanwhile, the number of compound spring blocks is selected to tune the desired electrical characteristics, such as impedance, of the MEMS resonator.

A multiple coil spring MEMS resonator includes a center anchor and a resonator body including two or more coil springs extending in a spiral pattern from the center anchor to an outer closed ring. Each pair of coil springs originates from opposing points on the center anchor and extends in the spiral pattern to opposing points on the outer ring. The number of coil springs, the length and the width of the coil springs and the weight of the outer ring are selected to realize a desired resonant frequency.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.