Zhigang Suo

Zhigang Suo

  • Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials
  • Area Dean for Materials Science and Mechanical Engineering
  • Kavli Scholar, Kavli Institute for Bionano Science & Technology

Profile

Devices in modern technologies (e.g., microelectronics, MEMS, photonics, and biosensors) are integrated structures of diverse materials, complex architectures, and small feature sizes. Their function, fabrication, and reliability pose urgent mechanics problems. As the experimental and computational capabilities change drastically, the division of labor is shifting: What to understand? What to measure? What to compute? Suo and his students aim to create scientific models of small-scale processes that have significant engineering consequences. The following examples illustrate the promise of future growth in mechanics.

Mechanics of nanofabrication. Mass-producing nanostructures is a great challenge of our time. Several fabrication processes have recently shown astonishing capabilities. For example, nanoimprint has brought time-honored printing technology to such an exquisite size scale. Mechanics has long played significant roles in manufacturing, such as metal forming, ceramic sintering, and polymer molding. More recently, success stories have accumulated in applying mechanics to nanoscale fabrication. Examples include the stability of a strained thin epitexial film against dislocation injection, and strain-induced self-assembly of quantum dots. In collaboration with electrical engineers at Princeton University, Suo and his students have recently studied the mechanics of fabricating zero-defect, strain-free SiGe films on oxides. The research has led to great improvement of the fabrication process.

Mechanics of self-assembly. As photolithography reaches its limit of resolution, many alternative patterning technologies are under intense investigation. Among them are various processes of self-assembly. What are the forces that assemble these structures? What structures can be produced? Suo and his students are studying molecules adsorbed on a solid surface, forming a pattern of disks or stripes, of stable sizes on the order 1-100 nm. The simulation of the group has suggested experimental means to form a perfect periodic pattern or, more remarkably, desired aperiodic patterns. The group is also exploring means for programmable transport of functional molecules on a chip.

Mechanics of durability. Nearly all materials in the on-chip interconnect structure have been changed in recent years. The feature size has already gone below 100 nm. Temperature cycling has long been used as a test to qualify devices. After being cycled between two temperatures, say -55C to 125C for 1000 times, a device is tested for its function, and then sectioned and examined in microscopes for failure modes (e.g., distortion and cracking). If a failure mode is found, one makes a new device by modifying either processing parameters, or geometry, or materials. The new device is temperature cycled again, followed by the microscopy examination. These make-and-break iterations are extremely time consuming. Scientific understanding of this test is of great value. In collaboration with researchers at Intel Corporation, Suo group has identified a new failure mechanism, called ratcheting-induced stable cracking (RISC). The mechanism shows how, in an integrated structure, the cycling temperature gradually breaks a brittle solid.

Contact Information

Office:309 Pierce Hall
Email:suo@seas.harvard.edu
Office Phone:(617) 495-3789
Assistant:LaShanda Banks
Assistant Office:Pierce Hall 318
Assistant Phone:617/496-1461

Primary Teaching Area

Materials Science & Mechanical Engineering

Positions & Employment

Harvard School of Engineering and Applied Sciences
  • July 2006-present: Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials
Division of Engineering and Applied Sciences
  • July 2003-July 2006: Gordon McKay Professor of Mechanics and Materials
Princeton University
  • July 1997-June 2003: Professor, Mechanical and Aerospace Engineering Department and Princeton Materials Institute
The University of California, Santa Barbara
  • July 1995-June 1997: Professor, Mechanical and Environmental Engineering Department and Materials Department
Max-Planck-Institute, Stuttgart
  • June-December 1994: Visiting scientist
The University of California, Santa Barbara
  • December 1993 June 1997: Joint Appointment, Materials Department
Brown University
  • July 1992: Visiting Associate Professor
The University of California, Santa Barbara
  • July 1992-June 1995: Associate Professor, Mechanical and Environmental Engineering Department
  • September 1989-June 1992: Assistant Professor, Mechanical and Environmental Engineering Department

Harvard University

  • June-September 1989: Postdoctoral Research Fellow
Xi'an Jiaotong University
  • June 1985-August 1986: Post-Graduate Researcher

Other Experience & Professional Membership

Professional Memberships

  • Member, the US National Academy of Engineering, Elected in 2008
  • Board Member, Proceedings of the Royal Society A: mathematical, physics and engineering sciences, January 2009-Present

Editorial

  • Editor, International Journal of Applied Mechanics, 2009-Present
  • Associate Editor, International Journal of Solids and Structures, 2005-Present
  • Consultant Editor, International Journal of Mechanical Engineering Education, 2005-Present
  • Associate Editor, ASME Journal of Applied Mechanics, 2003-2009
  • Associate Editor, ASME Journal of Electronic Packaging, 2001-2004
  • International Advisory Editorial Board, Acta Mechanica Solida Sinica, 2000-Present
  • Board of Editors, Computer Modeling in Engineering & Sciences, 2000-Present
  • Editorial Board, Engineering Fracture Mechanics, 1997-Present

Professional Activities

  • Co-chair, China-America Frontiers of Engineering Symposium, 2009
  • Co-chair, A workshop on mesoscale mechanics of complex materials, 2009
  • NSF proposal review pannel, 19 December 2008
  • Elected US delegate to ICTAM 2008 in Adelaide, Australia
  • Member, Scientific Advisory Board, Institute of High Performance Computing, Singapore, 2007-Present
  • Member at large, US National Committee of Theoretical and Applied Mechanics, 1 November 2006-31 October 2010
  • Co-founder (with Teng Li), iMechanica.org, the web of mechanics and mechanicians, 11 September 2006
  • Chair, Gordon Research Conference on Thin Film and Mechanical Behavior, Colby College, Waterville, Maine, 30 July-4 August 2006
  • Member, Executive Committee, Applied Mechanics Division, American Society of Mechanical Engineers, 2005-2010. Chair (July 2009 - June 1010)
  • Member, Scientific Advisory Board, Max-Planck-Institute for Metal Research, Stuttgart. 2002-2008. Second visit: Dec 7, 2004
  • Review of the DOE BES Materials and Engineering Physics Program at Los Alamos National Laboratories. 15 and 16 Nov. 2004
  • Discussion leader, Gordon Research Conference on Adhesion, 9 August 2004
  • Discussion leader, Gordon Research Conference on Thin Film and Small Scale Mechanical Behavior, 21 July 2004
  • NSF nanomanufacturing proposal review panel, 12 January 2004
  • Organizer (with Sean Corcoran, Young-Chang Joo, Neville Moody), Symposium U: Thin Films-Stresses and Mechanical Properties X. MRS Fall Meeting, 1-5 December 2003. Proceedings vol. 795
  • Co-chair, Nanoscale Phenomena Committee, ASME Nanotechnology Institute, 2003-Present
  • Chair (with Michael Kassner and Sia Nemat-Nasser), DOE Workshop on New Directions in Mechanics. 8-10 September 2003. Airlie Center, Warrenton, VA
  • Member, Scientific Advisory Board, Max-Planck-Institute for Metal Research, Stuttgart. 2002-2008. First visit: 13-15 November 2002
  • Chair-Elect, Gordon Conference on Thin Film Mechanical Behavior, 2006; Vice-chair, 2004
  • Discussion leader, Gordon Research Conference on Thin Film Mechanical Behavior, 16-21 July 2002
  • Chair, Electronic Materials Committee, Materials Division, American Society of Mechanical Engineers, 1999-2002
  • Organizer (with Rui Huang), Symposium on Mechanics of Thin Films and Other Small Structures. The 14th U.S. National Congress of Applied Mechanics, Virginia Tech, Blacksburg, VA. (Fourteen 125-minute sessions)
  • Guest Professor, Shanghai Jiaotong University, July 2001-2004
  • Organizer (with Jun He), Symposium on Thermomechanical Stability of Advanced Interconnects, ASME Winter Annual Meeting, New York City, November 2001. (Three 90-minute sessions.)
  • Organizer (with R. Dauskardt), Symposium on Nanoscale Materials and Structures, ASME Winter Annual Meeting, New York City, November 2001. (Four 90-minute sessions.)
  • Organizer (with Yiheng Chen and Jun Sun), Workshop of Mechanics and Materials in a New Century, Xian, China, 9-12 July 2001
  • Organizer (with Mahyar Dadkhah and Brian Cox), Symposium on Mechanics and Materials for Better Micro Devices and Packages, ASME Winter Meeting, Orlando, Florida. (six 90-minute sessions), November 2000
  • Panel for Review of AFOSR Mechanics Research Proposals, National Materials Advisory Board, August 10-11, 2000
  • Discussion leader, Gordon Research Conference on Thin Film Mechanical Behavior, 14-19 July 2000
  • Advisory Professor, Tongji University, June 2000-Present
  • Adjunct Professor, Xi'an Jiaotong University, May 2000-Present
  • NSF/DARPA Research Initiative Workshop on Sensitive Skin, Arlington Virginia, October 1999
  • NSF CAREER Proposal Panel, Mechanics and Materials Program, November 1998
  • Member, Executive Committee, Princeton Materials Institute, 1998-2003
  • Organizer (with J. Clement, R. Keller, K. Krisch, J. Sanchez), Simposium J: Materials Reliability in Microelectronics VII, Materials Research Society 1997 Spring Meeting, April 1997. MRS Symposium Proceedings Volume 473
  • NSF CAREER Proposal Panel, January 1996
  • Member, Young Investigator Advisory Committee, NSF Institute of Materials Mechanics, 1992-1995.
  • Conference Chair (David Marshall, co-chair), The Third Annual Meeting of the NSF Young Investigators in Mechanics and Materials: Structural Evolution in Materials. Rockwell Science Center, Thousand Oaks, California, 11, 12 November 1995
  • NSF Proposal Review Panel, June 1993

Honors

  • Humboldt Research Award, 2009
  • Midwest Mechanics Seminar, 2008/2009
  • Zhu Kezhen Distinguished Lecturer, American Zhu Kezhen Education Foundation, 2008
  • South West Mechanics Lecture Series (SWMLS), 2006
  • Special Achievement Award for Young Investigators in Applied Mechanics, Applied Mechanics Division, American Society of Mechanical Engineers, 2001
  • Eric Reissner Medal, International Conference on Computational Engineering and Science, 2000
  • Award for Excellence in Teaching, Engineering Council, Princeton University, 1999, 2000
  • Pi Tau Sigma Gold Medal, American Society of Mechanical Engineers, 1994
  • Alexander von Humboldt Research Fellow, Germany, 1994
  • Young Investigator Award, National Science Foundation, 1992
  • Research Initiation Award, National Science Foundation, 1990

Patents Awarded

Sigurd Wagner, Stephanie Lacour, Zhigang Suo. Stretchable and elastic interconnects. United States Patent 7,491,892