Nano- And Microelectromechanical Resonators

Description:

INV-16015

Background

Micro Electro Mechanical (MEM) resonators are key enablers for the development of miniaturized and low power multi-band radio-frequency (RF) systems capable of operating in the extremely crowded modern commercial and military spectral environment. Recently, the complete maturation of the Aluminum Nitride (AlN) Film-Bulk-Acoustic resonator (FBAR) technology has allowed the replacement of off-chip surface acoustic wave (SAW) devices in commercial products, hence enabling a significant reduction in the form-factor of their RF front-ends.

The high frequency Aluminum Nitride (AlN) Micro-Electro-Mechanical Systems (MEMS) contour mode resonator (CMR) technology has shown great potential for the implementation of single-chip, multi-frequency RF filters and frequency sources. The CMR technology has the same advantages of thin film bulk acoustic resonators (FBARs) in terms of miniaturization and IC integration capabilities. However, once the device resonant frequency is set by the thickness of the AlN plate as in the case of AlN FBAR technology, it cannot be further tuned lithographically and attaining a high quality factor along with large electromechanical coupling coefficients in small volumes has also been elusive.

Technology Overview

In this work, Northeastern University researchers present a new class of AlN MEM resonators based on the piezoelectric transduction of a Lame mode in the cross-section of an AlN plate.

The design of the proposed Cross-Sectional-Lame-Mode resonators (CLMRs) utilizes a coherent combination of piezoelectric coefficients of AlN to transduce a 2-dimensional (2D) mechanical mode of vibration, which is characterized by longitudinal vibrations along both the width and the thickness of the AlN plate. This feature enables the implementation of CLMRs with high values of electromechanical coupling coefficient (kt² as high as 7%). Furthermore, due to the dependence of 2D mode on the lateral dimensions of the plate, CLMRs operating at significantly different frequencies can be lithographically defined on the same substrate without requiring additional fabrication steps. These two features enable the integration of multi-frequency and low insertion-loss filters on the same chip with reduced costs and fabrication complexity.

Benefits

• High values of electromechanical coupling coefficient and figure of merit
• Low insertion-loss filters
• Reduction in the number of lithographic mask steps during fabrication
• Integration of CLMRs operating at significantly different frequencies (UHF and VHF) on the same chip
• Reduced cost due to a reduction in fabrication complexity

Applications

• Receiver and transmitter modules of RF front-ends implemented on the same chip
• Multi‑frequency and low insertion loss filter banks for reconfigurable radio‑frequency (RF) front‑ends
• RF filters and duplexers currently used in cellphones
• CMOS-MEMS oscillator as frequency reference for RF communication applications
• Band pass filters for RF communication applications
• Ultra-sensitive and fast MEMS resonant chemical, physical and bio-sensors

Opportunity

• Licensing
• Partnering
• Research Partner

Patents

• Aluminum Nitride Cross-Sectional Lame Mode Resonators- US Patent Number: 9,419,583
• Nano- And Microelectromechanical Resonators- US Patent Number: 9,712,136
• Nano- And Microelectromechanical Resonators- US Patent Number: 9,935,608

Seeking

• Development partner
• Commercial partner
• Licensing

IP Status

• Patented