"Silicon as a Mechanical Material"

Revisiting a seminal paper in MEMS and NEMS

Friday, April 19, 2019

About the Presentation

In 1982, Kurt Petersen at IBM Research Laboratory wrote the seminal review paper entitled Silicon as a Mechanical Material. In this paper, Petersen asserted that “silicon, in conjunction with its conventional role as an electronic material, and taking advantage of an already advanced microfabrication technology, can also be exploited as a high-precision high-strength high-reliability mechanical material, especially applicable wherever miniaturized mechanical devices and components must be integrated or interfaced with electronics”.

This single statement was one of the driving forces behind the development of microelectromechanical systems (MEMS) and later nanoelectromechanical systems (NEMS), which have since been incorporated into several industrial applications such as inkjet printers, accelerometers, gyroscopes, microphones, and digital micromirror devices.

However, the progression from idea to products has taken significant time and resources, in large part due to uncertain mechanical reliability. In particular, reliability issues related to the deformation and fracture of MEMS and NEMS silicon components have become increasingly important given continued reductions in critical feature sizes coupled with recent escalations in both device actuation forces and harsh usage conditions.

In this talk, key points from Petersen’s paper and subsequent studies on the mechanical properties of silicon are reviewed. This is followed by more detailed descriptions of several recent NIST studies on the deformation and fracture of MEMS and NEMS silicon components, with a particular emphasis on the rationale behind the test method and its ability to answer important yet open questions in the literature. Finally, the results from these studies and others are used to reconcile several of Petersen’s original statements, and also to generate one of the most comprehensive review papers to date on the strength of MEMS and NEMS silicon components.

About the Presenter

Dr. Frank DelRio

Group Leader, Fatigue and Fracture Group

National Institute of Standards and Technology (NIST)

Frank W. DelRio received a B.S. in Mechanical Engineering from Carnegie Mellon University in 1998, after which he worked as a Product Support Engineer at C&D Aerospace (now C&D Zodiac). In 2001, he returned to academia, ultimately receiving an M.S. in Mechanical Engineering from Boise State University in 2002 and a Ph.D. in Mechanical Engineering from the University of Colorado at Boulder in 2006. After working as a postdoctoral researcher at the University of California, Berkeley, he joined the Materials Science and Engineering Laboratory (now the Material Measurement Laboratory, MML) at the National Institute of Standards and Technology (NIST).

At NIST, Frank has served as the Leader of the Nanoscale Strength Measurements and Standards Project from 2007 to 2014, as the Leader of the Small-Scale Mechanics for Advanced Materials Project from 2014 to 2016, and as a Science Advisor in the MML Lab Office from 2016 to 2017.

Currently, he is the Leader of the Fatigue and Fracture Group, which conducts research on the fatigue and fracture of advanced structural materials for pipeline safety, hydrogen storage, additive manufacturing, and cardiac device reliability. His research focuses on the development and use of materials and assemblies for small-scale mechanical applications via advancements in stand-alone and integrative mechanical measurement and microscopy techniques, with an emphasis on advanced materials in electronics, biomedical and health, infrastructure, energy, and forensics applications.

In all, he has published more than 60 peer-reviewed papers in journals such as Nature Materials, PNAS, Nano Letters, and ACS Applied Materials and Interfaces. Frank is also the recipient of several awards and honors, including an ASME Orr Early Career Award, a Department of Commerce Bronze Medal Award, an Adhesion Society Outstanding Young Adhesion Scientist Award, and a Presidential Early Career Award for Scientists and Engineers.

Dr. DelRio has been named the 2019 Outstanding ME Alumnus. Please join us after the seminar for a light lunch and socializing.

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