MEMS and Nanotechnology Engineering Consultant

· Consulting for academic and industry clients on design, layout, process development, prototype fabrication, and transfer-to-manufacturing of MEMS devices.  Scope of work includes micro-sensors, customized AFM cantilever tips, bio-application needles, micro-fluidic devices, optical gratings, optical devices and circuit design; also includes technology review, background research and feasibility analysis.

Scientific Collaborator, University of Neuchatel, Switzerland

· Worked on the design and fabrication of liquid-compatible atomic force microscope (AFM) probe arrays for life-science applications. Successfully fabricated and tested 2D array of thin piezoresistive cantilevers and established standard process flow for such devices.

Visiting Scientist, Nanoscale Studies Dept, IBM Almaden Research Center, San Jose, California

· Worked with Dan Rugar's group on the use of magnetic resonance force microscopy (MRFM) for spin detection.  Focused on design and fabrication of custom mass-loaded cantilevers for ultra-sensitive force detection.  Cantilevers successfully used in the detection of single electron spins (Nature, July 2004; #1 AIP physics story of 2004).

Senior Design Engineer, Lightconnect Inc., Newark, California

· As employee #2, helped company grow from 2 to 60 people in three years. Fabricated prototype diffractive-MEMS chips used in company products (including variable optical attenuator and dynamic gain equalizer). Supervised transfer of technology to commercial foundry; worked with foundry to implement process development and yield improvements.

· Worked in Stanford Nanofabrication Facility performing wafer processing tasks, including lithography, thin film deposition, etching, metallization.



· Ph.D. in Electrical Engineering, Stanford University, June 1998.
Performed research on Atomic Force Microscope thermomechanical data storage under Prof. Thomas Kenny, in collaboration IBM Almaden Research Center.

· Specialized in micro-electro-mechanical system (MEMS) design and fabrication.

· Thesis: “Advanced micromachined cantilevers for AFM data storage and imaging.”

· Recipient of IBM Cooperative Graduate Fellowship, 1995-1998.


· M.S. and B.S. in electrical engineering, Stanford University, 1992 (GPA 4.0)

· Specialized in semiconductor device technology and VLSI design.

· Participated in six-month Stanford-in-Japan overseas program, 1991.


· Diocesan Boys’ School, Hong Kong (A-levels 1988, HKCEE 1986)



· Henry Ford II Scholar Award, 1992 (highest GPA in Stanford School of Engineering)

· Terman Engineering Award, 1991 (top 5% in engineering school)

· Member, Tau Beta Pi and Phi Beta Kappa

· Sir Edward Youde Memorial Scholarship for Overseas studies, Hong Kong, 1988

· Top 10 students out of 160,000 in Hong Kong high school graduation exam, 1986



· Designed and fabricated mass-loaded single-crystal silicon cantilevers with specially engineered thermal noise spectra for ultra-sensitive force detection in magnetic resonance force imaging.

· Designed, fabricated and tested novel dual-axis AFM cantilever with independent piezoresistive sensors for vertical and lateral force detection. Invented oblique ion implant technique for high-aspect-ratio microstructures (3 patents issued).

· Designed and built electronic servo controller for AFM data disk tracking and readback, using dual-axis piezoresistive cantilever mounted on modified compact-disk actuator.

· Designed, fabricated and tested 1-micron thick silicon cantilevers with integrated piezoresistors for atomic force microscope (AFM) data readback and resistive heaters for thermal writing.

· Developed ion implant and anneal process for making shallow piezoresistors on thin substrates, producing low-stiffness, high-sensitivity cantilevers.

· Optimized heater-cantilever design using ANSYS simulations, enabling the fabrication of micromachined heaters with 300-fold improvement in thermal response time.

· Gained extensive clean room experience, especially in silicon micromachining: photolithography, plasma etching, furnace oxidation, rapid thermal anneal, wet silicon etching, polyimide-film application, metal etching, deep Si etching.

· Languages: English, Chinese, elementary French and Japanese.  Interests: piano, tennis.




· "Microcantilevers for atomic force microscope data storage," S.D. Senturia, ed., Kluwer Academic Publ., 168 pages.

Book chapter (primary author):

· "Dual-axis piezoresistive AFM cantilever for independent detection of vertical and lateral forces," in Tribology Issues and Opportunities in MEMS, Kluwer Academic Publishers, Apr. 98.

MRFM-related papers:

· "Single spin detection by magnetic resonance force microscopy," D. Rugar, R. Budakian, H.J. Mamin, B.W. Chui, Nature, Vol. 430, pp. 329-332, July 2004.

· "Detection and manipulation of statistical polarization in small spin ensembles," H.J. Mamin, R. Budakian, B.W. Chui, D. Rugar, Phys. Rev. Lett., Vol. 91, 207604, 2003.

· "Manipulation and Detection of Electron Spins by Magnetic Resonance Force Microscopy," D. Rugar, R. Budakian, H.J. Mamin, B.W. Chui, AIP Conf. Proc. 696, 45, 2003.

Other journal publications (primary author):

· "Advanced temperature compensation for piezoresistive sensors based on crystallographic orientation," Rev. Sci. Instr., Vol. 78, No. 4, 2007.

· "Independent piezoresistive detection of vertical and lateral forces with a dual-axis atomic force microscope cantilever," Appl. Phys. Lett., Vol. 72, pp. 1388-90, 1998.

· "Low-stiffness silicon cantilevers with integrated piezoresistive sensors and resistive heaters for high-density AFM thermomechanical data storage," J. MEMS, Vol. 7, pp. 69-78, 1998.

· "Low-stiffness silicon cantilevers for thermal writing and piezoresistive readback with the atomic force microscope" Appl. Phys. Lett., vol. 69, pp. 2767-9, 1998.

Conference presentations and papers (primary author):

· "Mass-loaded cantilevers with suppressed higher-order modes for magnetic resonance force microscopy," proceedings of Transducers ‘03, pp. 1120-3, Boston, Aug. 2003.

· "Modeling of heat transfer and design optimization for high-speed heater-cantilever," poster, Transducers ‘01, Sendai, June 1999.

· "A novel approach to the design and fabrication of dual-axis high-aspect-ratio piezoresistive MEMS structures," poster, 7th Solid-state Sensor & Actuator Workshop, Hilton Head, June 1998.

· "Dual-axis piezoresistive cantilever for simultaneous detection of lateral and vertical forces," proceedings of MEMS 98, Heidelberg, Jan. 1998.

· "A novel piezoresistive AFM cantilever for simultaneous detection of lateral and vertical forces," proceedings of the ASME International Congress and Exposition, Dallas, Nov. 1997

· "Independent detection of lateral and vertical forces with a novel AFM piezoresistive cantilever," presented at the American Vacuum Society (AVS) 44th Annual Symposium, San Jose, Oct. 1997.

· "Micromachined heaters with 1-ms thermal time constants for AFM thermomechanical data storage," proceedings of Transducers ‘97, Chicago, June 1997.

· "Advanced cantilevers for AFM thermomechanical data storage," presented at the American Vacuum Society 43rd Annual Symposium, Philadelphia, Oct. 1996.

· "Improved cantilevers for AFM thermomechanical data storage," proceedings of 6th Solid-state Sensor and Actuator Workshop, Hilton Head, June 1996.

Updated July 2011