Abstract: The invention provides a microelectromechanical resonator device comprising a support structure and a resonator manufactured on a (100) or (110) semiconductor wafer, wherein the resonator is suspended to the support structure and comprises at least one beam being doped to a doping concentration of 1.1*1020 cm?3 or more with an n-type doping agent and is being capable of resonating in a length-extensional, flexural resonance or torsional mode upon suitable actuation. In particular, the doping concentration and angle of the beam are chosen so as to simultaneously produce zero or close to zero second order TCF, and even more preferably zero or close to zero first and second order TCFs, for the resonator in said resonance mode, thus providing a temperature stable resonator.

Abstract: The invention concerns microelectromechanical resonators. In particular, the invention provides a resonator comprising a support structure, a doped semiconductor resonator suspended to the support structure by at least one anchor, and actuator for exciting resonance into the resonator. According to the invention, the resonator comprises a base portion and at least one protrusion extending outward from the base portion and is excitable by said actuator into a compound resonance mode having temperature coefficient of frequency (TCF) characteristics, which are contributed by both the base portion and the at least one protrusion. The invention enables simple resonators, which are very well temperature compensated over a wide temperature range.

Abstract: In a bulk acoustic wave (BAW) filter based on laterally acoustically coupled resonators on piezoelectric thin films, one can utilize two distinct acoustic plate wave modes of different nature, for example the thickness extensional (longitudinal) TE1 and the second harmonic thickness shear (TS2) mode to form a bandpass response. The invention is based on the excitation of at least two lateral standing wave resonances belonging to different plate wave modes that facilitate the transmission of signal. The passband is designed by tailoring the wave propagation characteristics in the device such that the resonances are excited at suitable frequencies to form a passband of a desired shape. The bandwidth of the filter described herein may therefore be more than twice that of the existing state-of-the-art microacoustic filters. Consequently, it has significant commercial and technological value.

Abstract: The invention relates to a laterally coupled bulk acoustic wave (LBAW) filter comprising a vibration layer for carrying bulk acoustic waves, electrode means comprising a first electrode coupled to the vibration layer for exciting to the vibration layer at least one longitudinal wave mode having a first frequency band and one shear wave mode having a second frequency band, and a second electrode coupled to the vibration layer for sensing the filter pass signal, the first and second electrodes being laterally arranged with respect to each other, and an acoustic reflector structure in acoustic connection with the vibration layer. According to the invention, the reflector structure is adapted to acoustically isolate the vibration layer from its surroundings at the first frequency band more efficiently than at the second frequency band for suppressing the effect of the shear wave mode at the second frequency band from the filter pass signal. The invention helps to improve the quality of LBAW filter passbands.

Abstract: In a bulk acoustic wave (BAW) filter based on laterally acoustically coupled resonators on piezoelectric thin films, one can utilize two distinct acoustic plate wave modes of different nature, for example the thickness extensional (longitudinal) TE1 and the second harmonic thickness shear (TS2) mode to form a bandpass response. The invention is based on the excitation of at least two lateral standing wave resonances belonging to different plate wave modes that facilitate the transmission of signal. The passband is designed by tailoring the wave propagation characteristics in the device such that the resonances are excited at suitable frequencies to form a passband of a desired shape. The bandwidth of the filter described herein may therefore be more than twice that of the existing state-of-the-art microacoustic filters. Consequently, it has significant commercial and technological value.

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.

Abstract: The invention describes a manufacturing method for an acoustic balanced-unbalanced (balun) or balanced-balanced thin-film BAW filter based on lateral acoustic coupling. In laterally acoustically coupled thin-film BAW filters (LBAW) one can realize transformation from unbalanced to balanced electric signal if the electrodes of the balanced port are placed on the opposite sides of the piezoelectric film. The manufacturing process is simpler than in the corresponding component based on vertical acoustical coupling. The device can also realize impedance transformation.

Abstract: The invention relates to temperature compensated micro-electro-mechanical (MEMS) resonators (300) preferably made of silicon. Prior art MEMS resonators have a significant temperature coefficient of resonance frequency, whereby it is difficult to achieve a sufficiently good frequency stability. The inventive MEMS resonator has a resonance plate (310) which resonates in Lamé mode. The resonance plate is p+ doped material, such as silicon doped with boron, and the concentration of the p+ doping is such that the plate has a temperature coefficient of resonance frequency near to zero. The tensile stress and the second order temperature coefficient can further be reduced by doping the plate with germanium.

Abstract: The invention relates to a laterally coupled bulk acoustic wave (LBAW) filter comprising a vibration layer for carrying bulk acoustic waves, electrode means comprising a first electrode coupled to the vibration layer for exciting to the vibration layer at least one longitudinal wave mode having a first frequency band and one shear wave mode having a second frequency band, and a second electrode coupled to the vibration layer for sensing the filter pass signal, the first and second electrodes being laterally arranged with respect to each other, and an acoustic reflector structure in acoustic connection with the vibration layer. According to the invention, the reflector structure is adapted to acoustically isolate the vibration layer from its surroundings at the first frequency band more efficiently than at the second frequency band for suppressing the effect of the shear wave mode at the second frequency band from the filter pass signal. The invention helps to improve the quality of LBAW filter passbands.

Abstract: The invention relates to a microelectromechanical resonators and a method of manufacturing thereof. The resonator comprises at least two resonator elements made from semiconductor material, the resonator elements being arranged laterally with respect to each other as an array, at least one transducer element coupled to said resonator elements and capable of exciting a resonance mode to the resonator elements. According to the invention, said at least one transducer element is a piezoelectric transducer element arranged laterally with respect to the at least two resonator elements between the at least two resonator elements and adapted to excite to the resonator elements as said resonance mode a resonance mode whose resonance frequency is dependent essentially only on the c44 elastic parameter of the elastic modulus of the material of the resonator elements. By means of the invention, electrostatic actuation and problems associated therewith can be avoided and accurate resonators can be manufactured.

Abstract: The invention concerns a micromechanical device and method of manufacturing thereof. The device comprises an oscillating or deflecting element made of semiconductor material comprising n-type doping agent and excitation or sensing means functionally connected to said oscillating or deflecting element. According to the invention, the oscillating or deflecting element is essentially homogeneously doped with said n-type doping agent. The invention allows for designing a variety of practical resonators having a low temperature drift.

Abstract: The invention relates to an acoustically coupled thin-film BAW filter, comprising a piezoelectric layer, an input-port on the piezoelectric layer changing electrical signal into an acoustic wave (SAW, BAW), and an output-port on the piezoelectric layer changing acoustic signal into electrical signal. In accordance with the invention the ports include electrodes positioned close to each other, and the filter is designed to operate in first order thickness-extensional TE1 mode.

Abstract: The invention relates to a micromechanical device comprising a semiconductor element capable of deflecting or resonating and comprising at least two regions having different material properties and drive or sense means functionally coupled to said semiconductor element. According to the invention, at least one of said regions comprises one or more n-type doping agents, and the relative volumes, doping concentrations, doping agents and/or crystal orientations of the regions being configured so that the temperature sensitivities of the generalized stiffness are opposite in sign at least at one temperature for the regions, and the overall temperature drift of the generalized stiffness of the semiconductor element is 50 ppm or less on a temperature range of 100° C. The device can be a resonator. Also a method of designing the device is disclosed.

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.

Abstract: In a bulk acoustic wave (BAW) filter based on laterally acoustically coupled resonators on piezoelectric thin films, one can utilize two distinct acoustic plate wave modes of different nature, for example the thickness extensional (longitudinal) TE1 and the second harmonic thickness shear (TS2) mode to form a bandpass response. The invention is based on the excitation of at least two lateral standing wave resonances belonging to different plate wave modes that facilitate the transmission of signal. The passband is designed by tailoring the wave propagation characteristics in the device such that the resonances are excited at suitable frequencies to form a passband of a desired shape. The bandwidth of the filter described herein may therefore be more than twice that of the existing state-of-the-art microacoustic filters. Consequently, it has significant commercial and technological value.

Abstract: The invention relates to a micromechanical device comprising a semiconductor element capable of deflecting or resonating and comprising at least two regions having different material properties and drive or sense means functionally coupled to said semiconductor element. According to the invention, at least one of said regions comprises one or more n-type doping agents, and the relative volumes, doping concentrations, doping agents and/or crystal orientations of the regions being configured so that the temperature sensitivities of the generalized stiffness are opposite in sign at least at one temperature for the regions, and the overall temperature drift of the generalized stiffness of the semiconductor element is 50 ppm or less on a temperature range of 100° C. The device can be a resonator. Also a method of designing the device is disclosed.

Abstract: The invention relates to a micromechanical resonator comprising a substrate (1) of first material (2), a resonator (3) suspended to the supporting structure (1), the resonator (3) being at least partially of the same material (2) as the supporting structure and dimensioned for resonation at a specific frequency f0, coupling means (5) for initiating, maintaining and coupling the resonation of the resonator (3) to an external circuit (6), and the resonator (3) including second material (4), the thermal properties of which being different from the first material (2). In accordance with the invention the resonator (3) includes the second material (4) located concentrated in specific places of the resonator (3).

Abstract: The invention describes a manufacturing method for an acoustic balanced-unbalanced (balun) or balanced-balanced thin-film BAW filter based on lateral acoustic coupling. In laterally acoustically coupled thin-film BAW filters (LBAW) one can realize transformation from unbalanced to balanced electric signal if the electrodes of the balanced port are placed on the opposite sides of the piezoelectric film. The manufacturing process is simpler than in the corresponding component based on vertical acoustical coupling. The device can also realize impedance transformation.

Abstract: The invention relates to a microelectromechanical resonators and a method of manufacturing thereof. The resonator comprises at least two resonator elements made from semiconductor material, the resonator elements being arranged laterally with respect to each other as an array, at least one transducer element coupled to said resonator elements and capable of exciting a resonance mode to the resonator elements. According to the invention, said at least one transducer element is a piezoelectric transducer element arranged laterally with respect to the at least two resonator elements between the at least two resonator elements and adapted to excite to the resonator elements as said resonance mode a resonance mode whose resonance frequency is dependent essentially only on the c44 elastic parameter of the elastic modulus of the material of the resonator elements. By means of the invention, electrostatic actuation and problems associated therewith can be avoided and accurate resonators can be manufactured.

Abstract: The invention relates to temperature compensated micro-electro-mechanical (MEMS) resonators (300) preferably made of silicon. Prior art MEMS resonators have a significant temperature coefficient of resonance frequency, whereby it is difficult to achieve a sufficiently good frequency stability. The inventive MEMS resonator has a resonance plate (310) which resonates in Lamé mode. The resonance plate is p+ doped material, such as silicon doped with boron, and the concentration of the p+ doping is such that the plate has a temperature coefficient of resonance frequency near to zero. The tensile stress and the second order temperature coefficient can further be reduced by doping the plate with germanium.