Details of the Researcher

PHOTO

Vergara Pulgar Andrea Alejandra
Section
Graduate School of Engineering
Job title
Assistant Professor
e-Rad No.
70961192

Research History 3

  • 2025/04 - Present
    Tohoku University　Graduate School of Engineering　Assistant Professor

  • 2024/06 - 2025/03
    Tohoku University　Micro System Integration Center　Assistant Professor

  • 2021/10 - 2024/05
    Tohoku University　Graduate School of Engineering　Assistant Professor

Education 3

  • Tohoku University　Graduate School of Engineering　Department of Robotics

    2018/10 - 2021/09

  • Tohoku University　Graduate School of Engineering　Department of Robotics

    2017/10 - 2018/09

  • University of Chile　Faculty of Physical and Mathematical Sciences

    2009/04 - 2015/03

Committee Memberships 2

  • Transducers 2025　Technical Program Committee

    2024/12 - 2025/07

  • Transducers　Student Engagement Committee, Member

    2021/04 - 2021/06

Professional Memberships 3

  • IEEE Member

    2021/11 - Present

  • 日本機械学会

    2020/11 - Present

  • 電気学会

    2020/11 - Present

Research Interests 3

  • Piezoresistive sensor

  • Piezoelectric thin film devices

  • MEMS

Research Areas 1

  • Nanotechnology/Materials / Nano/micro-systems /

Awards 2

  1. Encouragement Award

    2025/11　Institute of Electrical Engineers of Japan

  2. Best Oral Presentation Award

    2022/01　IEEE MEMS 2022　FEEDBACK CONTROLLED PZT MICROMIRROR WITH INTEGRATED BURIED PIEZORESISTORS

Papers 14

  1. Design and fabrication of non-resonant PZT MEMS micromirror with buried piezoresistors for closed loop position control Invited Peer-reviewed

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    Journal of Micromechanics and Microengineering　33　(1)　014001-014001　2022/11/18

    Publisher: IOP Publishing

    DOI： 10.1088/1361-6439/aca101 　

    ISSN： 0960-1317

    eISSN： 1361-6439

    More details Close

    Abstract This paper reports on a 1D PZT micromirror integrated with buried piezoresistors for quasi-static feedback position control. The piezoresistors located along or below the PZT actuators could achieve the sensitivity as high as 3.1 mV/°, which was two orders of magnitude higher than the traditional ones located at the torsion springs (8.2 μV/°). This increased the signal-to-noise ratio by 2 orders of magnitude, which could enable the accurate position control. The response of the longitudinal sensors along the beams had a fast settling time less than 1 ms. The average position error was 0.975%, which was much better than that from the conventional shear stress sensor on the torsion bar of 3.1%.

  2. Basic Characteristics of a Small Strain Sensor using p-n Junction Breakdown Peer-reviewed

    Andrea Vergara, Yukio Suzuki, Tatsuya Matsumoto, Shuji Tanaka

    IEEJ Transactions on Sensors and Micromachines　2026/08/01

    DOI： 10.1541/ieejsmas.146.205 　

    ISSN： 1341-8939 1347-5525

  3. Fabrication and characterization of piezoelectric micromachined ultrasonic transducer using silicon-on-nothing structure and single crystal PZT thin film

    Zhengnan Tang, Andrea Vergara, Shuji Tanaka

    2026

    DOI： 10.2139/ssrn.7361159 　

  4. Feasibility Study of Layer Separation Using Patterned Internal Laser Damage in Silicon Peer-reviewed

    Yuan Yao, Andrea Vergara, Zhengnan Tang, Shuji Tanaka

    IEEJ Transactions on Electrical and Electronic Engineering　2026/01

    DOI： 10.1002/tee.70136 　

    ISSN： 1931-4973 1931-4981

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    <jats:title>Abstract</jats:title> <jats:p> Laser lift‐off (LLO) technology is widely used to separate ultra‐thin electronic devices and in advanced packaging but typically relies on a specialized laser‐responsive layer, adding complexity. This paper presents an innovative take on stealth dicing by using a pulsed laser in a two‐dimensional plane to create a separation interface without requiring a special layer, thus simplifying the fabrication process. The relationship between shear strength and laser ablation parameters was analyzed through shear force tests, with the modified layer morphology also examined. Shear strength for separation ranged from 200 to 20 MPa, with lower values achieved by reducing scanning pitch, increasing laser power, or enlarging the separated area. These findings highlight the potential of 2D stealth dicing as an LLO technique for ultra‐thin devices. © 2025 The Author(s). <jats:italic>IEEJ Transactions on Electrical and Electronic Engineering</jats:italic> published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. </jats:p>

  5. Acoustic Radiation Actuator by Amplitude-Modulated PMUT for Microspeaker Demonstration Peer-reviewed

    Juan Pablo Romero-Campos, Andrea Vergara, Shuji Tanaka

    Journal of Microelectromechanical Systems　2026

    DOI： 10.1109/JMEMS.2026.3713307 　

  6. Irreversible Membrane Deformation and Other Defects in Silicon-on-Nothing Structures: Experimental Insights and Cavity Pressure Characterization Peer-reviewed

    Zhengnan Tang, Andrea Vergara, Shuji Tanaka

    Journal of Microelectromechanical Systems　2026

    DOI： 10.1109/JMEMS.2026.3687890 　

  7. Investigation on liquid medium integration for piezoelectric MEMS tunable liquid lenses Peer-reviewed

    Zhengnan Tang, Andrea Vergara, Taiyu Okatani, Yukio Suzuki, Shuji Tanaka

    Sensors and Actuators A: Physical　377　115732-115732　2024/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.sna.2024.115732 　

    ISSN： 0924-4247

  8. Non-linear Behavior of pMUT for High Sound Pressure Generation Peer-reviewed

    Wei Fang, Andrea Vergara, Shuji Tanaka

    IEEJ Transactions on Sensors and Micromachines　144　(6)　149-155　2024/06/01

    Publisher: Institute of Electrical Engineers of Japan (IEE Japan)

    DOI： 10.1541/ieejsmas.144.149 　

    ISSN： 1341-8939

    eISSN： 1347-5525

  9. PZT Mems Tunable Liquid Lens with Integrated Piezoresistive Position Sensor Peer-reviewed

    Zhengnan Tang, Leo Soda, Taiyu Okatani, Andrea Vergara, Yukio Suzuki, Shuji Tanaka

    2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers)　835-838　2023/06

  10. Feedback control of thin film PZT MEMS actuator with integrated buried piezoresistors Peer-reviewed

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    Sensors and Actuators A: Physical　332　113131-113131　2021/12

    DOI： 10.1016/j.sna.2021.113131 　

    ISSN： 0924-4247

    eISSN： 1873-3069

  11. Piezoelectric micromirror with embedded buried piezoresistors for position control

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    MN2-09A3-2　2021/11

  12. PZT MEMS Actuator with Integrated Buried Piezoresistors for Position Control

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)　2021-　626-629　2021/01/25

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/MEMS51782.2021.9375422 　

    ISSN： 1084-6999

  13. Integration of buried piezoresistive sensors and PZT thin film for dynamic and static position sensing of MEMS actuator Peer-reviewed

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    Journal of Micromechanics and Microengineering　30　(11)　115020-115020　2020/11

    DOI： 10.1088/1361-6439/abb756 　

    ISSN： 0960-1317

    eISSN： 1361-6439

  14. Soft modular robotic cubes: Toward replicating morphogenetic movements of the embryo Peer-reviewed

    Vergara, A., Lau, Y.-S., Mendoza-Garcia, R.-F., Zagal, J.C.

    PLoS ONE　12　(1)　e0169179-e0169179　2017/01

    Publisher: Public Library of Science (PLoS)

    DOI： 10.1371/journal.pone.0169179 　

    ISSN： 1932-6203

    eISSN： 1932-6203

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Misc. 1

  1. 薄膜PZTアクチュエータとピエゾ抵抗センサを有するMEMS可変焦点液体レンズ—MEMS Varifocal Liquid Lens with PZT Thin Film Actuators and Piezoresistive Sensors

    Zhengnan Tang, Leo Soda, 岡谷 泰佑, Andrea Vergara, 鈴木 裕輝夫, 田中 秀治

    「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編]　40　4p　2023/11

    Publisher: [東京] : Institute of Electrical Engineers of Japan

Presentations 16

  1. Non-linear Behavior of pMUT for High Sound Pressure Generation

    Wei Fang, Andrea Vergara, Shuji Tanaka

    2023/11/08

  2. 薄膜PZTアクチュエータとピエゾ抵抗センサを有するMEMS可変焦点液体レンズ—MEMS Varifocal Liquid Lens with PZT Thin Film Actuators and Piezoresistive Sensors

    Zhengnan Tang, Leo Soda, 岡谷 泰佑, Andrea Vergara, 鈴木 裕輝夫, 田中 秀治

    「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編]　2023/11

  3. PZT MEMS Varifocal Lens using Gel or Liquid as Optical Media

    Zhengnan Tang, Leo Soda, Andrea Vergara, Yukio Suzuki, Shuji Tanaka

    2022/11

  4. Simultaneous poling of multiple piezoelectric devices

    Andrea Vergara, Samuel Hsieh, Shuji Tanaka

    第39回「センサ・マイクロマシンと応用システム」シンポジウム　2022/11

  5. FEEDBACK CONTROLLED PZT MICROMIRROR WITH INTEGRATED BURIED PIEZORESISTORS

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    IEEE MEMS 2022　2022/01/13

  6. Feedback Controlled Pzt Micromirror with Integrated Buried Piezoresistors

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2022 IEEE 35th International Conference on Micro Electro Mechanical Systems Conference (MEMS)　2022/01/09

  7. Feed-back control of PZT actuator with built-in buried piezoresistors

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2021/11/10

  8. Piezoelectric micromirror with embedded buried piezoresistors for position control

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2021/11/09

  9. Feed-back control of PZT actuator with built-in buried piezoresistors

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2021/11/09

  10. PZT MEMS ACTUATOR WITH INTEGRATED BURIED PIEZORESISTORS FOR POSITION CONTROL

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    IEEE MEMS 2021　2021/01/28

  11. PZT MEMS Actuator with Integrated Buried Piezoresistors for Position Control

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS)　2021/01/25

  12. Piezoelectric MEMS actuator monolithically integrated with buried piezoresistors for position sensing

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2020/10/28

  13. Piezoelectric MEMS actuator monolithically integrated with buried piezoresistors for position sensing

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2020/10/19

  14. Integration of buried piezoresistive sensors and PZT thin film for highly stable MEMS actuator

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2020/01/30

  15. PZT thin film actuator with integrated buried piezoresistive sensors for high precision and stability

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2019/11/20

  16. PZT thin film actuator with integrated buried piezoresistive sensors for high precision and stability

    Andrea Vergara, Takashiro Tsukamoto, Weileun Fang, Shuji Tanaka

    2019/11/12

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Teaching Experience 2

  1. Mathematics II (IMAC-U)　Tohoku University

  2. Computer Seminar I　Tohoku University Undergraduate (liberal arts)