Rf Micro Devices, Inc.

Integrated Device Technology, Inc.

Seungbae Lee

Kushal Bhattacharjee

Sheng-Shian Li

Harmeet Bhugra

Ye Wang

Ashwin K Samarao

A method for making a micro-electro-mechanical systems (MEMS) vibrating structure is disclosed. The MEMS is supported by a MEMS anchor system and includes a single-crystal piezoelectric thin-film layer that has a specific non-standard crystal orientation, which may be selected to increase an electromechanical coupling coefficient, decrease a temperature coefficient of frequency, or both. The MEMS vibrating structure may have dominant lateral vibrations or dominant thickness vibrations. The single-crystal piezoelectric thin-film layer may include Lithium Tantalate or Lithium Niobate, and may provide MEMS vibrating structures with precise sizes and shapes, which may provide high accuracy and enable fabrication of multiple resonators having different resonant frequencies on a single substrate.

Method for manufacturing a vibrating MEMS circuit

A periodic signal generator is configured to generate high frequency signals characterized by relatively low temperature coefficients of frequency (TCF). A microelectromechanical resonator, such as concave bulk acoustic resonator (CBAR) supporting capacitive and piezoelectric transduction, may be geometrically engineered as a signal generator that produces two periodic signals having unequal resonant frequencies with unequal temperature coefficients. Circuitry is also provided for combining the two periodic signals using a mixer to thereby yield a high frequency low-TCF periodic difference signal at an output of the periodic signal generator.

Periodic signal generators having microelectromechanical resonators therein that support generation of high frequency low-TCF difference signals

A microelectromechanical resonator includes a resonator body, which is encapsulated within a sealed cavity extending between first and second substrates that are bonded together. The resonator body is anchored to the first substrate by at least a pair of tethers that suspend the resonator body opposite an underlying recess in the first substrate. A resistive heating element is provided, which is configured to indirectly heat the resonator body through convective heating of the cavity. This resistive heating element may be disposed on an inner surface of the second substrate that is exposed to the cavity. The resonator may also include first and second electrical interconnects, which extend through the second substrate and contact respective first and second portions of the resistive heating element.

Microelectromechanical resonators having resistive heating elements therein configured to provide frequency tuning through convective heating of resonator bodies

A method of forming a device is provided. The method includes providing a substrate, forming a sacrificial layer over the substrate, and forming an field layer around the sacrificial layer. After formation, both the sacrificial layer and the field layer are planarized. A component is then formed over the planarized sacrificial layer and the planarized field layer. The component has a first electrode and a second electrode and a single crystal wafer disposed between the first electrode and the second electrode. The component also includes anchors disposed substantially over the field layer. Once the component is formed, the sacrificial layer is released with an etchant having a selectivity for the sacrificial layer such that a cavity is formed beneath the component. The cavity allows free movement component within the cavity during operation of the device. In addition, the etchant does not release the field layer and the component such that the field layer remains below the anchors.

Planarized sacrificial layer for MEMS fabrication

Micro-electromechanical acoustic resonators include a substrate having a cavity therein and a resonator body suspended over the cavity. The resonator body is anchored on opposing sides thereof (by support beams) to first and second portions of the substrate. These first and second portions of the substrate, which extend over the cavity as first and second ledges, respectively, each have at least one perforation therein disposed over the cavity. These perforations may be open or filled. The first and second ledges are formed of a first material (e.g., silicon) and the first and second ledges are filled with a second material having a relatively high acoustic impedance relative to the first material. This second material may include a material selected from a group consisting of tungsten (W), copper (Cu), molybdenum (Mo).

Thin-film bulk acoustic resonators having perforated resonator body supports that enhance quality factor

The present invention relates to a micro-electro-mechanical systems (MEMS) vibrating structure supported by a MEMS anchor system, and includes a single-crystal piezoelectric thin-film layer having domain inversions, which determine certain vibrational characteristics of the MEMS vibrating structure. The MEMS vibrating structure may have dominant lateral vibrations or dominant thickness vibrations. The single-crystal piezoelectric thin-film layer may include Lithium Tantalate or Lithium Niobate, and may provide MEMS vibrating structures with precise sizes and shapes, which may provide high accuracy and enable fabrication of multiple resonators having different resonant frequencies on a single substrate.

MEMS vibrating structure using a single-crystal piezoelectric thin-film layer having domain inversions

Micro-Electro-Mechanical Systems (MEMS) resonator designs having support structures that minimize or substantially reduce anchor losses, thereby improving a quality factor (Q) of the MEMS resonators, are provided. In general, a MEMS resonator includes a resonator body connected to anchors via support structures. The anchors are connected to or are part of a substrate on which the MEMS resonator is formed. The support structures operate to support the resonator body in free space to enable vibration. The support structures are designed to minimize or substantially reduce energy loss through the anchors into the substrate.

Anchor/support design for MEMS resonators

The present invention relates to a multi-mode micro-electromechanicalsystems (MEMS) resonator system that may provide low motional resistance and a high quality factor by using a resonating structure that includes multiple parallel-coupled longitudinally resonating bodies, each of which has multiple resonating segments adjacent to one another along an axis. The multi-mode MEMS resonator system may provide high acoustic velocity by using the micro-structure of MEMS technology. The multi-mode MEMS resonator system may include electrostatic transducers, piezoelectric transducers, or both. The present invention includes multiple embodiments that may include different configurations of the resonating structure.

Multi-mode MEMS resonator array

The present invention relates to a micro-electro-mechanical systems (MEMS) vibrating structure having dominant lateral vibrations supported by a MEMS anchor system, and includes a single-crystal piezoelectric thin-film layer that has been grown with a specific crystal orientation. Since the MEMS vibrating structure has dominant lateral vibrations, its resonant frequency may be controlled by its size and shape, rather than layer thickness, which provides high accuracy and enables multiple resonators having different resonant frequencies on a single substrate.

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Greensboro, NC, United States of America

Seungbae Lee