Internal Electrostatic Transduction Resonators
- Technology Benefits
- Dielectric materials such as TiO2 or HfO2 are not just CMOS compatible and qualified, they are already available in state-of-the-art CMOS foundries.Lateral bulk resonators with narrow trenches that are filled with the transducing dielectric can be deposited conformally using atomic layer deposition. To date, growing high quality trench side-walls has not been achieved with piezoelectric materials such as ZnO or AiN.This transduction scheme is not limited by the third overtone; long strip resonators running at very high overtones can be fabricated. This structure will further increase transduction efficiency and enables two-port resonators with small feed-through as well as passive mixers, at RF frequencies.These resonators have structural elements that are very similar to vertical channel FinFET transistors, thereby enabling built-in active impedance transformation which will greatly simplify the use of resonator arrays as signal processing structures or computing substrates.High electric fields are confined within the resonator, which eliminates the reliability concerns of exposed surfaces with high electric fields.Eliminating the air-gap significantly improves fabrication yields.
- Technology Application
- Micromechanical filters, oscillators and mixers.
- Detailed Technology Description
- None
- Supplementary Information
- Patent Number: US7522019B2
Application Number: US2005146303A
Inventor: Bhave, Sunil A. | Howe, Roger T.
Priority Date: 4 Jun 2004
Priority Number: US7522019B2
Application Date: 3 Jun 2005
Publication Date: 21 Apr 2009
IPC Current: H03H000900 | H03H0009125
US Class: 333187 | 333188
Assignee Applicant: The Regents of the University of California
Title: Internal electrostatic transduction structures for bulk-mode micromechanical resonators
Usefulness: Internal electrostatic transduction structures for bulk-mode micromechanical resonators
Summary: As a micromechanical resonator such as a film bulk acoustic resonator (FBAR), e.g. for operation at around 1.9 GHz or above.
Novelty: Bulk mode micromechanical resonator e.g. film bulk acoustic resonator has electrostatic transducer with dielectric layer filled between electrodes, located at maximum strain antinode of microresonator to transduce resonator acoustic modes
- Industry
- Electronics
- Sub Category
- Semiconductor
- Application No.
- 7522019
- Others
-
Tech ID/UC Case
17358/2004-051-0
Related Cases
2004-051-0
- *Abstract
-
Multiple resonators with different frequencies are essential in the design of micromechanical filters, oscillators and mixers. Lateral-mode resonators with a variety of resonant frequencies can be fabricated in the same lithography step using surface micromachining technology. However, these lateral-mode resonators have inefficient air-gap capacitive transducers that cause high motional impedance.
To address this problem, researchers at the University of California, Berkeley have developed an electrostatic transducer for lateral-mode resonators in which the electrode gaps are filled with a dielectric material that has much higher permittivity than air. Previous dielectric transduction mechanisms rely on Poisson coupling between the SiN and silicon. However, this internal electrostatic transducer is directly coupled to the bulk acoustic mode of the lateral silicon resonator. As a result, the Berkeley design enables more efficient coupling between the transducer and resonator, and offers the potential to make an FBAR device entirely out of TiO2 instead of AiN.
This internal electrostatic transducer has several advantages over both air-gap electrostatic and piezoelectric transduction including: lower motional impedance, compatibility with advanced scaled CMOS device technology, and extended dynamic range. Moreover, energy losses are minimized in the Berkeley transducer by matching the acoustic velocity of the dielectric material to the acoustic velocity of the resonator material.
- *IP Issue Date
- Apr 21, 2009
- *Principal Investigator
-
Name: Sunil Bhave
Department:
Name: Roger Howe
Department:
- Country/Region
- USA
