Electrical Engineering

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Seung-Deok Ko

School of Electrical and Computer Engineering, Georgia Institute of Technology

E-mails: ****.****@*****.*** / Phone: +01-858-***-**** Professional Experience

Postdoc researcher, Georgia Institute of Technology, Advisor: Farrokh Ayazi (2016.09-present) 1. Development of “high-Q silicon carbide disk resonator” (sponsored by DARPA) Silicon carbide BAW resonator with Q over 1M realized by wafer-scale bonding of Silicon carbide on Insulator

(SiCOI) wafer and high aspect ratio trench etching in silicon carbide substrate Postdoc researcher, UC San Diego, Advisor: Gabriel M. Rebeiz (2015.10-2016.08) 2. Development of “Set and forget RF MEMS capacitor” (sponsored by DARPA) A “set and forget MEMS RF capacitor” realized by adopting the t-shaped, very thin, electro-thermomechanical fuse tethers. (capacitance change from 0.2pF to 1.5pF with Q around 100) Research Assistant, KAIST, Advisor: Jun-Bo Yoon (2008.3-2016.02) 3. Development of vertical/lateral micro mechanical switch fabrication with various sacrificial layer Fabrication processes achieved excellent yields (>95%) with various switch designs including bridge, cantilever, comb-drive, folded beam, and curved electrode structures 4. Measurement of stress in nano-thin film via beam deflection method (sponsored by Samsung Electronics) Residual stress of nano-scale thin film is measured by measuring the deflection of cantilever arrays 5. Metal nanoparticle electrical contact lubricant for micro/nano-mechanical switch Dramatic electrical contact resistance reduction (80%) and prolonged lifetime (~10 times) of MEMS switches were achieved by nanoparticle electrical contact lubrication 6. Insulating liquid as an electrical contact lubricant for micro/nano mechanical switches Discovery and analysis of remarkable 94% adhesion force reduction in MEMS structure by adopting insulating liquid environment

Education

B.S. (Magna Cum Laude), Dept. of Physics, KAIST, Daejeon, Korea 2004.03-2008.02 Ph.D. School of Electrical Engineering, KAIST, Daejeon, Korea Thesis: Study on the Topographic Approach for Lifetime Enhancement of MEMS Switches 2008.03-2016.02

Skills

Fabrication Dry-etch (ICP, RIE, O2 Ashing), wet-etch, thin film deposition (sputtering, evaporation, PECVD, LPCVD, thermal oxidation), UV lithography, Cu/Ni/Au electroless/electro-plating, high aspect-ratio photoresist (SU-8, AZ9260, AZ50XT, thickness >10μm), critical point drying, lapping and chemical mechanical polishing, UV Contact aligner (MA 6, MJB4, Q7000), furnace, stylus profiler (Keyence, Alpha-step, Zygo), confocal fluorescent microscope, parameter analyzer, contact angle analyzer, scanning electron microscope (SEM), Energy Dispersive x-ray Spectroscopy (EDAX), Atomic Force Microscopy (AFM), wafer bonding

RF ADS, HFSS, VNA, power meter, packaging

Software Tool Matlab, Java, C++, Python, L-Edit, Comsol, CoventorWare Honors and Awards

Co-recipient of the best paper award in oral session, Korean MEMS conference, 2015

Korea research student scholarship, Korea Student Aid Foundation (2008.03~2010.02)

Samsung Junior Frontier Leader (JFL) Scholarship, Samsung SDS (2004.03~2008.02) 2

Publications

International Journal

1. Seung-Deok Ko, Chang-Hoon Han, Keun-Seo Lim, Min-Ho Seo and Jun-Bo Yoon “Investigation of the Nanoparticle Electrical Contact Lubrication in MEMS Switches,” Journal of Microelectromechanical Systems, Vol. 26, no. 6, pp. 1417-1427, Dec. 2017.

2. Chang-Hoon Han, Min-Ho Seo, Seung-Deok Ko, Young-Hoon Yoon, Gun-Wook Yoon and Jun-Bo Yoon

"Unconventional Use of a Photoresist as a Nitrogen Gas Generator Forming Transparent Dome-Shaped Microcavities" Advanced Engineering Materials, Vol. 18, Issue. 4, pp. 559-566, Apr. 2016. 3. Yong-Hoon Yoon, Yong-Ha Song, Seung-Deok Ko, Chang-Hoon Han, Geon-Sik Yun, and Jun-Bo Yoon "A Highly Reliable MEMS Relay with Two-step Spring System and Heat Sink Insulator for High Power Switching Applications," Journal of Microelectromechanical Systems, Vol. 25, No. 1, pp. 217-226, Dec. 2015. 4. Yong-Ha Song, Seung-Deok Ko and Jun-Bo Yoon, "A Highly Reliable 2-Axis MEMS Relay Demonstrating a Novel Contact Refresh Method," Journal of Microelectromechanical Systems, Vol. 24, No. 5, pp. 1495-1502, Oct. 2015.

5. Yong-Ha Song, Sang-Joon Kenny Ahn, Min-Wu Kim, Jeong-Oen Lee, Chi-Sun Hwang, Jae-Eun Pi, Seung- Deok Ko, Kwang-Wook Choi, Sang-Hee Ko Park and Jun-Bo Yoon, "High-Performance Hybrid Complementary Logic Inverter through Monolithic Integration of a MEMS Switch and an Oxide TFT," Small, Vol. 11, Issue 12, pp. 1390-1395, Mar. 2015.

6. Min-Wu Kim, Yong-Ha Song, Seung-Deok Ko, Sang-Joon Ahn and Jun-Bo Yoon, "Ultra-low Voltage MEMS Switch Using a Folded Hinge Structure," Micro and Nano Systems Letters, Vol. 2, No. 2, pp.1-5, Jun. 2015. 7. Yong-Ha Song, Min-Wu Kim, Jeong Oen Lee, Seung-Deok Ko and Jun-Bo Yoon, "Complementary Dual- Contact Switch Using Soft and Hard Contact Materials for Achieving Low Contact Resistance and High Reliability Simultaneously," Journal of Microelectromechanical Systems, Vol. 22, Issue. 4, pp. 846-854, Aug. 2013.

8. Seok-Ho Song, Hyun-Ho Yang, Chang-Hoon Han, Seung-Deok Ko, Seok-Hee Lee and Jun-Bo Yoon, "Metal- Oxide-Semiconductor Field Effect Transistor Humidity Sensor Using Surface Conductance," Applied Physics Letters, Vol. 100, Issue 10, 101603, Feb. 2012.

9. Seung-Deok Ko, Jeong Oen Lee, Hyun-Ho Yang, Min-Wu Kim, Yong-Ha Song and Jun-Bo Yoon, "An Insulating Liquid Environment for Reducing Adhesion in a Microelectromechanical System," Applied Physics Letters, Vol. 99, Issue 11, 113516, Sep. 2011.

10. Dong Seok Kim, Seung-Deok Ko, Seung Jun Lee, Byung-Kee Lee, Jun-Bo Yoon and Do Kyung Kim,

"Investigation on the Electrical Contact Behaviors of RF-MEMS Switches Using Nano-indenter," Reviews on Advanced Materials Science, Vol. 28, No. 1, pp. 17-20, Jun. 2011. International Conferences

1. Seung-Deok Ko, Benoit Hamelin, Jeremy Yang and Farrokh Ayazi, “High-Q Monocrystalline Silicon Carbide Disk Resonators Fabricated using DIRE of Thick-SiC-on-Insulator Subsrates,” IEEE MEMS 2018 conference, Belfast Waterfront, UK, Jan. 2018 (accepted).

2. Jun-Bo Yoon, Yong-Hoon Yoon, Min-Ho Seo, Seung-Deok Ko, Yong-Ha Song, Min-Wu Kim, Hyun-Ho Yang, Jeong Oen Lee, and Weon-Wi Jang. "Efforts toward ideal microelectromechanical switches."," TRANSDUCERS 2017. 19th International Conference on Solid-state Sensors, Actuators and Microsystems, Kaohsiung, Taiwan, pp. 171-174, Jun. 2017. 3. Jae-Shin Lee, Seung-Deok Ko, Chang-Hoon Han, Yong-Hoon Yoon, Min-Ho Seo, and Jun-Bo Yoon,

“Inductance enhancement of a MEMS inductor with self-aligned magnetic nanoparticles,” IEEE MEMS 2017 conference, Las Vegas, USA, pp. 893-896, Jan. 2017. 3

4. Min-Ho Seo, Eunhwan Jo, Seung-Deok Ko, Dae-Sung Kwon, Yong-Hoon Yoon, Jungwook Choi, Jongbaeg Kim, and Jun-Bo Yoon “Carbon nanotubes network contact lubrication for highly reliable MEMS switch,” IEEE MEMS 2017 conference, Las Vegas, USA, pp. 5-8, Jan. 2017. 5. Yong-Hoon Yoon, Yong-Ha Song, Seung-Deok Ko, Chang-Hoon Han, Geon-Sik Yun, Min-Ho Seo and Jun-Bo Yoon, "Highly Reliable MEMS Relay with Two-step Spring System and Heat Sink Insulator for Power Applications," IEEE MEMS 2015 conference, Portugal, pp 114-117, Jan. 2017. 6. Hyun-Ho Yang, Seung-Deok Ko, Jeong Oen Lee and Jun-Bo Yoon, "A New N/MEMS-Based Nonvolatile Circuit," TRANSDUCERS 2011. 16th International Conference on Solid-state Sensors, Actuators and Microsystems, Beijing, China, pp. 52-55, Jun. 2011. 7. Jeong-Oen Lee, Min-Wu Kim, Seung-Deok Ko and Jun-Bo Yoon, "Annealing Effect on Contact Characteristics in TiN based 3-Terminal NEMS Relays," IEEE NANO 2010-10th International Conference on Nanotechnology, Goyang-Si, Korea, pp.1-4, Aug. 2010.

8. Jeong-Oen Lee, Min-Wu Kim, Seung-Deok Ko, Hee-Oh Kang, Woo-Ho Bae, Min-Ho Kang, Ki-Nam Kim, Dong-Eun Yoo and Jun-Bo Yoon, "3-Terminal Nanoelectromechanical Switching Device in Insulating Liquid Media for Low Voltage Operation and Reliability Improvement," IEDM 2009, IEEE International Electron Devices Meeting, Hilton Baltimore, USA, pp.227-230, Dec. 2009. Patents

1. Jun-Bo Yoon, Yong-Hoon Yoon, Yong-Ha Song, Seung-Deok Ko, Chang-Hoon Song, Geon-Sik Yun, Min-Ho Seo, Cheol ho Kim and Byung Jun Seo, "Electrostatic switch", South Korea, Registration number 101**********, Dec. 28. 2016.

References

Gabriel M. Rebeiz, Professor, Ph.D. (E-mail: ******@***.****.***, Phone: +01-858-***-****) Department of Electrical and Computer Engineering, UCSD, San Diego, California

Jun-Bo Yoon, Professor, Ph.D. (E-mail: ******@**.*****.**.**, Phone: +82-42-350-****) Professor, Dept. of Electrical Engineering, KAIST, Daejeon, Korea

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