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*10.sup.20 cm.sup.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.

A method for designing a narrowband acoustic wave microwave filter including: generating a modeled filter circuit design having circuit elements including an acoustic resonant element defined by an electrical circuit model that includes a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss; and generating a final circuit design. Generating the final circuit design includes optimizing the modeled filter circuit design to generate an optimized filter circuit design; comparing a frequency response of the optimized filter circuit design to requirements; selecting the optimized filter circuit design for construction into the actual acoustic microwave filter based on the comparison; and transforming the optimized filter circuit design to a design description file for input to a construction process.

A method for designing a narrowband acoustic wave microwave filter including: generating a modeled filter circuit design having circuit elements including an acoustic resonant element defined by an electrical circuit model that includes a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss; and generating a final circuit design. Generating the final circuit design includes optimizing the modeled filter circuit design to generate an optimized filter circuit design; comparing a frequency response of the optimized filter circuit design to requirements; selecting the optimized filter circuit design for construction into the actual acoustic microwave filter based on the comparison; and transforming the optimized filter circuit design to a design description file for input to a construction process.

An elastic wave device includes an interdigital transducer electrode, a dielectric film, and a frequency adjustment film are disposed on a LiNbO.sub.3 substrate. When Euler Angles of the LiNbO.sub.3 substrate are within a range of about 0??5?, within a range of about ??1.5?, within a range of about 0??10?, the interdigital transducer electrode includes a main electrode, a film thickness of the main electrode normalized by a wavelength determined in accordance with an electrode finger pitch of the interdigital transducer electrode is denoted as T, and a density ratio of a material of the main electrode to Pt is denoted as r, the film thickness of the main electrode and ? of the Euler Angles satisfy ?=?0.05?/(T/r?0.04)+31.35?.

An elastic wave device includes a LiNbO.sub.3 substrate, an IDT electrode provided on the LiNbO.sub.3 substrate, and a dielectric film that is provided on the LiNbO.sub.3 substrate so as to cover the IDT electrode and includes a projection on an upper surface of the stated dielectric film. A main mode of an elastic wave excited by the IDT electrode uses a Rayleigh wave, and a thickness of the IDT electrode is set such that a frequency at which a response by an SH wave appears is lower than a resonant frequency of the Rayleigh wave.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

Embodiments of a Surface Acoustic Wave (SAW) device, or filter, and methods of fabrication thereof are disclosed. In some embodiments, the SAW filter comprises a piezoelectric substrate and an Interdigitated Transducer (IDT) on a surface of the piezoelectric substrate. The IDT includes multiple fingers, each comprising a metal stack. The SAW filter further includes a cap layer on a surface of the IDT opposite the piezoelectric substrate and on areas of the surface of the piezoelectric substrate exposed by the IDT. The cap layer has a thickness in a range of and including 10 to 500 Angstroms and a high electrical resistivity (and thus a low electrical conductivity). For instance, in some embodiments, the electrical resistivity of the cap layer is greater than 10 kilo-ohm meters (K.Math.m). The SAW filter further includes an oxide overcoat layer on a surface of the cap layer opposite the IDT and the piezoelectric substrate.

Embodiments of a Surface Acoustic Wave (SAW) device, or filter, and methods of fabrication thereof are disclosed. In some embodiments, the SAW filter comprises a piezoelectric substrate and an Interdigitated Transducer (IDT) on a surface of the piezoelectric substrate. The IDT includes multiple fingers, each comprising a metal stack. The SAW filter further includes a cap layer on a surface of the IDT opposite the piezoelectric substrate and on areas of the surface of the piezoelectric substrate exposed by the IDT. The cap layer has a thickness in a range of and including 10 to 500 Angstroms and a high electrical resistivity (and thus a low electrical conductivity). For instance, in some embodiments, the electrical resistivity of the cap layer is greater than 10 kilo-ohm meters (K.Math.m). The SAW filter further includes an oxide overcoat layer on a surface of the cap layer opposite the IDT and the piezoelectric substrate.

A method of designing an acoustic microwave filter in accordance with frequency response requirements comprises generating a modeled filter circuit design having a plurality of circuit elements comprising an acoustic resonant element defined by an electrical circuit model that comprises a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss. The method further comprises optimizing the modeled filter circuit design to generate an optimized filter circuit design, comparing a frequency response of the optimized filter circuit design to the frequency response requirements, and constructing the acoustic microwave filter from the optimized filter circuit design based on the comparison.