University of Pennsylvania ScholarlyCommons Departmental Papers (ESE) Department of Electrical & Systems Engineering 1-2010 Super-High-Frequency Two-Port AlN Contour-Mode Resonators for RF Applications Matteo Rinaldi University of Pennsylvania, [email protected] Chiara Zuniga University of Pennsylvania, [email protected] FChengjieollow this Z anduo additional works at: https://repository.upenn.edu/ese_papers University of Pennsylvania, [email protected] Part of the Acoustics, Dynamics, and Controls Commons, Electrical and Electronics Commons, ElectrGianlucao-Mechanical Piazza Systems Commons, Electronic Devices and Semiconductor Manufacturing Commons, NanoscienceUniversity of P andennsylv Nanotechnologyania, [email protected] Commons, Nanotechnology Fabrication Commons, Signal Processing Commons, and the Systems and Communications Commons Recommended Citation Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, and Gianluca Piazza, "Super-High-Frequency Two-Port AlN Contour-Mode Resonators for RF Applications", . January 2010. Copyright 2010 IEEE. Reprinted from: Rinaldi, M.; Zuniga, C.; Zuo, C.; Piazza, G., "Super-high-frequency two-port AlN contour-mode resonators for RF applications," Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on , vol.57, no.1, pp.38-45, Jan. 2010 Publisher URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5361520&isnumber=5361508 Digital Object Identifier: 10.1109/TUFFC.2010.1376 This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it. This paper is posted at ScholarlyCommons. https://repository.upenn.edu/ese_papers/522 For more information, please contact [email protected]. Super-High-Frequency Two-Port AlN Contour-Mode Resonators for RF Applications Abstract This paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices are employed to synthesize the highest frequency MEMS filter (3.7 GHz) based on AlN contour-mode resonator technology ever reported. Keywords Super High Frequency, Ultra-Thin-Film AlN, Nanoscaled Contour-Mode Resonators, MEMS Resonators, MEMS Filters, NEMS Disciplines Acoustics, Dynamics, and Controls | Electrical and Computer Engineering | Electrical and Electronics | Electro-Mechanical Systems | Electronic Devices and Semiconductor Manufacturing | Nanoscience and Nanotechnology | Nanotechnology Fabrication | Signal Processing | Systems and Communications Comments Copyright 2010 IEEE. Reprinted from: Rinaldi, M.; Zuniga, C.; Zuo, C.; Piazza, G., "Super-high-frequency two-port AlN contour-mode resonators for RF applications," Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on , vol.57, no.1, pp.38-45, Jan. 2010 Publisher URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5361520&isnumber=5361508 Digital Object Identifier: 10.1109/TUFFC.2010.1376 This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it. This journal article is available at ScholarlyCommons: https://repository.upenn.edu/ese_papers/522 38 IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL, vol. 57, no. 1, JANUARY 2010 Super-High-Frequency Two-Port AlN Contour-Mode Resonators for RF Applications Matteo Rinaldi, Student Member, IEEE, Chiara Zuniga, Student Member, IEEE, Chengjie Zuo, Student Member, IEEE, and Gianluca Piazza, Member, IEEE Abstract—This paper reports on the design and experimen- resonator (CMR) technology [3], [5] has emerged as one of tal verification of a new class of thin-film (250 nm) super- the most promising solutions in enabling the fabrication high-frequency laterally-vibrating piezoelectric microelectro- of multiple frequency and high performance resonators on mechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above the same silicon chip. In fact, the CMR technology can 3 GHz. The device dimensions have been opportunely scaled combine in a single device many important features that both in the lateral and vertical dimensions to excite a contour- characterize existing resonators (Fig. 1). The piezoelectric extensional mode of vibration in nanofeatures of an ultra-thin transduction enables simultaneous frequency scaling of (250 nm) AlN film. In this first demonstration, 2-port resona- the device and its direct interface to 50-Ω electronics. This tors vibrating up to 4.5 GHz have been fabricated on the same 2 is an extremely important advantage for RF applications die and attained electromechanical coupling, kt , in excess of 1.5%. These devices are employed to synthesize the highest (no matching networks with associated insertion losses are frequency MEMS filter (3.7 GHz) based on AlN contour-mode required) and it is not easily achievable with electrostati- resonator technology ever reported. cally-transduced resonators, for which frequency scaling is generally associated with an increase in the device imped- ance [6]. Even if an improved device impedance at higher I. Introduction frequency of operation was demonstrated using internal dielectric transduction [2], the values of the device imped- n recent years, the use of micro- and nanoelectrome- ance were still considerably high. In addition, the CMR Ichanical (MEMS/NEMS) resonators for RF applica- technology has the same advantages of thin film bulk tions has been widely explored. The development of com- acoustic resonators (FBAR) over SAW devices in terms pact, low cost, high-performance resonators is meant to of miniaturization and IC integration capabilities. Filters respond to the growing demand of single-chip, multi-band exhibiting SHF and relatively large bandwidth (3%) uti- RF solutions for advanced wireless communication sys- lizing FBARs have been demonstrated [7], [8]. In contrast tems. In addition, considering the rapid extension of wire- to FBAR, the CMR technology enables the fabrication of less networks in the super-high-frequency (SHF) band, for multiple frequencies of operation on the same silicon chip. example 3.6 GHz (802.11y) and 5 GHz (802.11a), the need This feature is crucial for advanced wireless communica- for resonators operating in the SHF band is steadily grow- tion systems, for which single-chip, multi-band RF solu- ing. In this context, the scaling of MEMS/NEMS devices tions are becoming the dominant trend. in the SHF band can have a tremendous impact because it High-performance AlN CMR devices in the very- and will enable the fabrication of high-performance frequency ultra-high-frequency (VHF-UHF) bands with quality fac- control devices that, thanks to their compact form factor tors between 1,000 and 4,000 have been previously dem- and IC integration capability, can be employed instead onstrated [5], [11]. Nevertheless, the capability of this of cumbersome and unintegrable SAW devices, in next technology to operate in the SHF band has not been generation RF front-ends. In particular the fabrication of extensively explored to date. Although one-port NEMS high-performance SHF channel-selector filters enables the laterally-vibrating AlN resonators based on lateral field implementation of receiver architectures capable of direct excitation (LFE) have been recently demonstrated by our conversion at SHF with additional benefits in terms of group [12], the unconventional electrode configuration of complexity, cost, and power consumption. those devices (bottom electrode not necessary for LFE) Different MEMS resonator technologies based on elec- prevented the nanoresonators from being easily configured trostatic [1], [2] or piezoelectric [3], [4] transduction have as 2-port networks, and hence fabrication of narrow-band been investigated. Among these, the AlN contour-mode filters. In this work, the thickness field excitation (TFE) CMR design is introduced to expand the frequency of op- Manuscript received May 19, 2009; accepted September 29, 2009. This eration of this technology in the SHF band to synthesize work was supported by