{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/102949"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/102949","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Optimization and design of radio frequency piezoelectric MEMS resonators","abstract":"Radio frequency (RF) microelectromechanical system (MEMS) resonators employing Lamb waves propagating in piezoelectric thin films have recently attracted much attention since they combine the advantages of the bulk acoustic wave (BAW) and surface acoustic wave (SAW) technologies: high phase velocity and multiple frequencies on a single chip. In particular, aluminum nitride (AlN) resonators based on fundamental symmetric (S0) Lamb mode have shown great promise because they can offer high phase velocities (10,000 m/s), low dispersive phase velocity characteristic, small temperature-induced frequency drift, low motional resistance, and monolithic integration compatibility with complementary metal–oxide–semiconductor (CMOS). However, there are still a few outstanding technical challenges, including spurious modes suppression, quality factor (Q) enhancement, frequency scalability, and electromechanical coupling improvement. These issues obstruct the wide deployment and commercialization of AlN Lamb mode resonators. This dissertation presents comprehensive investigations and solutions to these issues. This thesis is organized as follows: Chapter 1 gives a brief introduction of the basics on piezoelectric MEMS resonators and their promising applications. Chapter 2 first investigates the various available Lamb wave modes in AlN and then identifies the S0 mode as the promising resonator solution to overcome several challenges associated with SOA. Chapter 2 also discusses several outstanding challenges with S0 devices, including spurious mode suppression, Q enhancement, scaling resonant frequency, and enlarging fractional bandwidth. In response, Chapters 3-7 address these outstanding challenges by developing new designs and models, resorting to new acoustic mode, and incorporating new piezoelectric material. More specifically, Chapter 3 proposes two techniques to suppress the spurious modes in the responses of S0 resonators, namely mode conversion and mode shifting. Chapter 4 address the challenge of a conventionally vague question of reflection at the interface between released and unreleased regions in S0 resonators, and then demonstrates Q enhanced resonators with defined released regions achieved by a sandbox process. Chapter 5 first characterizes the S1 Lamb mode and optimizes its resonator configuration. A high-frequency S1 resonator at 3.5 GHz with a coupling of 3.5% is fabricated and demonstrated. Chapter 6 presents a hybrid filtering topology with a mode conversion AlN S0 resonator and lumped elements for widening the bandwidths of resonator-based filters. Chapter 7 proposes lithium niobate (LiNbO3) multilayered resonators with large electromechanical coupling, structure robustness, and good temperature stability. The analysis of Bragg reflectors, resonator simulation, stress control, fabrication, and measurements are covered in this chapter.","abstract_html":"Radio frequency (RF) microelectromechanical system (MEMS) resonators employing Lamb waves propagating in piezoelectric thin films have recently attracted much attention since they combine the advantages of the bulk acoustic wave (BAW) and surface acoustic wave (SAW) technologies: high phase velocity and multiple frequencies on a single chip. In particular, aluminum nitride (AlN) resonators based on fundamental symmetric (S0) Lamb mode have shown great promise because they can offer high phase velocities (10,000 m/s), low dispersive phase velocity characteristic, small temperature-induced frequency drift, low motional resistance, and monolithic integration compatibility with complementary metal–oxide–semiconductor (CMOS). However, there are still a few outstanding technical challenges, including spurious modes suppression, quality factor (Q) enhancement, frequency scalability, and electromechanical coupling improvement. These issues obstruct the wide deployment and commercialization of AlN Lamb mode resonators. This dissertation presents comprehensive investigations and solutions to these issues. This thesis is organized as follows: Chapter 1 gives a brief introduction of the basics on piezoelectric MEMS resonators and their promising applications. Chapter 2 first investigates the various available Lamb wave modes in AlN and then identifies the S0 mode as the promising resonator solution to overcome several challenges associated with SOA. Chapter 2 also discusses several outstanding challenges with S0 devices, including spurious mode suppression, Q enhancement, scaling resonant frequency, and enlarging fractional bandwidth. In response, Chapters 3-7 address these outstanding challenges by developing new designs and models, resorting to new acoustic mode, and incorporating new piezoelectric material. More specifically, Chapter 3 proposes two techniques to suppress the spurious modes in the responses of S0 resonators, namely mode conversion and mode shifting. Chapter 4 address the challenge of a conventionally vague question of reflection at the interface between released and unreleased regions in S0 resonators, and then demonstrates Q enhanced resonators with defined released regions achieved by a sandbox process. Chapter 5 first characterizes the S1 Lamb mode and optimizes its resonator configuration. A high-frequency S1 resonator at 3.5 GHz with a coupling of 3.5% is fabricated and demonstrated. Chapter 6 presents a hybrid filtering topology with a mode conversion AlN S0 resonator and lumped elements for widening the bandwidths of resonator-based filters. Chapter 7 proposes lithium niobate (LiNbO3) multilayered resonators with large electromechanical coupling, structure robustness, and good temperature stability. The analysis of Bragg reflectors, resonator simulation, stress control, fabrication, and measurements are covered in this chapter.","abstract_has_math":false,"creators":["Gao, Anming"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Gong, Songbin","Schutt-Ainé, José E.","Li, Xiuling","Zhou, Jin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-02-08T18:44:41Z","date_published":"2019-02-08T18:44:41Z","updated_at":"2026-07-22T22:24:42Z","subjects":["AlN, RF MEMS, piezoelectric, resonator"],"languages":["en"],"rights":["Copyright 2018 Anming Gao"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/102949","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gong, Songbin","Schutt-Ainé, José E.","Li, Xiuling","Zhou, Jin"]},{"key":"dc:creator","label":"Author","values":["Gao, Anming"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-02-08T18:44:41Z","2021-02-09T10:15:41Z","2018-12-07","2018-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["AlN, RF MEMS, piezoelectric, resonator"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2018 Anming Gao"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/102949"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Radio frequency (RF) microelectromechanical system (MEMS) resonators employing Lamb waves propagating in piezoelectric thin films have recently attracted much attention since they combine the advantages of the bulk acoustic wave (BAW) and surface acoustic wave (SAW) technologies: high phase velocity and multiple frequencies on a single chip. In particular, aluminum nitride (AlN) resonators based on fundamental symmetric (S0) Lamb mode have shown great promise because they can offer high phase velocities (10,000 m/s), low dispersive phase velocity characteristic, small temperature-induced frequency drift, low motional resistance, and monolithic integration compatibility with complementary metal–oxide–semiconductor (CMOS). However, there are still a few outstanding technical challenges, including spurious modes suppression, quality factor (Q) enhancement, frequency scalability, and electromechanical coupling improvement. These issues obstruct the wide deployment and commercialization of AlN Lamb mode resonators. This dissertation presents comprehensive investigations and solutions to these issues. This thesis is organized as follows: Chapter 1 gives a brief introduction of the basics on piezoelectric MEMS resonators and their promising applications. Chapter 2 first investigates the various available Lamb wave modes in AlN and then identifies the S0 mode as the promising resonator solution to overcome several challenges associated with SOA. Chapter 2 also discusses several outstanding challenges with S0 devices, including spurious mode suppression, Q enhancement, scaling resonant frequency, and enlarging fractional bandwidth. In response, Chapters 3-7 address these outstanding challenges by developing new designs and models, resorting to new acoustic mode, and incorporating new piezoelectric material. More specifically, Chapter 3 proposes two techniques to suppress the spurious modes in the responses of S0 resonators, namely mode conversion and mode shifting. Chapter 4 address the challenge of a conventionally vague question of reflection at the interface between released and unreleased regions in S0 resonators, and then demonstrates Q enhanced resonators with defined released regions achieved by a sandbox process. Chapter 5 first characterizes the S1 Lamb mode and optimizes its resonator configuration. A high-frequency S1 resonator at 3.5 GHz with a coupling of 3.5% is fabricated and demonstrated. Chapter 6 presents a hybrid filtering topology with a mode conversion AlN S0 resonator and lumped elements for widening the bandwidths of resonator-based filters. Chapter 7 proposes lithium niobate (LiNbO3) multilayered resonators with large electromechanical coupling, structure robustness, and good temperature stability. The analysis of Bragg reflectors, resonator simulation, stress control, fabrication, and measurements are covered in this chapter.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","The student, Anming Gao, accepted the attached license on 2018-12-06 at 16:56.","The student, Anming Gao, submitted this Dissertation for approval on 2018-12-06 at 17:02.","This Dissertation was approved for publication on 2018-12-07 at 09:21.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13245 on 2019-02-08 at 11:41:32","Made available in DSpace on 2019-02-08T18:44:41Z (GMT). No. of bitstreams: 3 GAO-DISSERTATION-2018.pdf: 21086317 bytes, checksum: 150d3fc09b815d3a0111ea1596f80bc0 (MD5) LICENSE.txt: 4207 bytes, checksum: f0498610c67f4a5bc576c7acaa59c416 (MD5) PROQUEST_LICENSE.txt: 4553 bytes, checksum: 7660b1569ae20630bbf63ddcd89d2190 (MD5) Previous issue date: 2018-12-07","Embargo set by: Seth Robbins for item 109977 Lift date: 2021-02-08T18:44:50Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 109977 on 2021-02-09T10:15:41Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Optimization and design of radio frequency piezoelectric MEMS resonators"]}]}],"canonical_facts":{"dc:contributor":["Gong, Songbin","Schutt-Ainé, José E.","Li, Xiuling","Zhou, Jin"],"dc:creator":["Gao, Anming"],"dc:date":["2019-02-08T18:44:41Z","2021-02-09T10:15:41Z","2018-12-07","2018-12"],"dc:description":["Radio frequency (RF) microelectromechanical system (MEMS) resonators employing Lamb waves propagating in piezoelectric thin films have recently attracted much attention since they combine the advantages of the bulk acoustic wave (BAW) and surface acoustic wave (SAW) technologies: high phase velocity and multiple frequencies on a single chip. In particular, aluminum nitride (AlN) resonators based on fundamental symmetric (S0) Lamb mode have shown great promise because they can offer high phase velocities (10,000 m/s), low dispersive phase velocity characteristic, small temperature-induced frequency drift, low motional resistance, and monolithic integration compatibility with complementary metal–oxide–semiconductor (CMOS). However, there are still a few outstanding technical challenges, including spurious modes suppression, quality factor (Q) enhancement, frequency scalability, and electromechanical coupling improvement. These issues obstruct the wide deployment and commercialization of AlN Lamb mode resonators. This dissertation presents comprehensive investigations and solutions to these issues. This thesis is organized as follows: Chapter 1 gives a brief introduction of the basics on piezoelectric MEMS resonators and their promising applications. Chapter 2 first investigates the various available Lamb wave modes in AlN and then identifies the S0 mode as the promising resonator solution to overcome several challenges associated with SOA. Chapter 2 also discusses several outstanding challenges with S0 devices, including spurious mode suppression, Q enhancement, scaling resonant frequency, and enlarging fractional bandwidth. In response, Chapters 3-7 address these outstanding challenges by developing new designs and models, resorting to new acoustic mode, and incorporating new piezoelectric material. More specifically, Chapter 3 proposes two techniques to suppress the spurious modes in the responses of S0 resonators, namely mode conversion and mode shifting. Chapter 4 address the challenge of a conventionally vague question of reflection at the interface between released and unreleased regions in S0 resonators, and then demonstrates Q enhanced resonators with defined released regions achieved by a sandbox process. Chapter 5 first characterizes the S1 Lamb mode and optimizes its resonator configuration. A high-frequency S1 resonator at 3.5 GHz with a coupling of 3.5% is fabricated and demonstrated. Chapter 6 presents a hybrid filtering topology with a mode conversion AlN S0 resonator and lumped elements for widening the bandwidths of resonator-based filters. Chapter 7 proposes lithium niobate (LiNbO3) multilayered resonators with large electromechanical coupling, structure robustness, and good temperature stability. The analysis of Bragg reflectors, resonator simulation, stress control, fabrication, and measurements are covered in this chapter.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","The student, Anming Gao, accepted the attached license on 2018-12-06 at 16:56.","The student, Anming Gao, submitted this Dissertation for approval on 2018-12-06 at 17:02.","This Dissertation was approved for publication on 2018-12-07 at 09:21.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13245 on 2019-02-08 at 11:41:32","Made available in DSpace on 2019-02-08T18:44:41Z (GMT). No. of bitstreams: 3 GAO-DISSERTATION-2018.pdf: 21086317 bytes, checksum: 150d3fc09b815d3a0111ea1596f80bc0 (MD5) LICENSE.txt: 4207 bytes, checksum: f0498610c67f4a5bc576c7acaa59c416 (MD5) PROQUEST_LICENSE.txt: 4553 bytes, checksum: 7660b1569ae20630bbf63ddcd89d2190 (MD5) Previous issue date: 2018-12-07","Embargo set by: Seth Robbins for item 109977 Lift date: 2021-02-08T18:44:50Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 109977 on 2021-02-09T10:15:41Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/102949"],"dc:language":["en"],"dc:rights":["Copyright 2018 Anming Gao"],"dc:subject":["AlN, RF MEMS, piezoelectric, resonator"],"dc:title":["Optimization and design of radio frequency piezoelectric MEMS resonators"],"dc:type":["text"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:42Z"}