The National Nuclear Security Administration (NNSA) will award $17 million over the next five years to research that aims to make microelectromechanical systems (MEMS) more reliable and durable for commercial and defense applications.

The research center being established at Purdue University, the Center for Prediction of Reliability, Integrity and Survivability of Microsystems (Prism), is one of five new Centers of Excellence chosen by the NNSA. It will involve about 35 Purdue researchers working in collaboration with those from the University of Illinois at Urbana-Champaign and the University of New Mexico.

The centers will all focus on unclassified applications of interest to NNSA and its three national laboratories -- Lawrence Livermore, Los Alamos and Sandia -- with lab personnel serving as advisers and collaborators.

The Purdue center, which will focus on the behavior and reliability of miniature switches, will advance the emerging field of "predictive science," or applying computational simulations to predict the behavior of complex systems, said Jayathi Y. Murthy, director of the new center and a professor in Purdue's School of Mechanical Engineering.

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A tiny radio frequency microelectromechanical system (MEMS) switch. The device has a length of about 400 µm (roughly four times the width of a human hair). The National Nuclear Security Administration has awarded $17 million to a research center being built at Purdue University to develop advanced simulations for perfecting the devices for commercial and defense applications. (Image courtesy Dimitrios Peroulis, Purdue School of Electrical and Computer Engineering, Birck Nanotechnology Center)

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Prism, which will be based at the Birck Nanotechnology Center in Purdue's Discovery Park, will be funded with $17 million over five years from the NNSA's Office of Advanced Simulation and Computing through its Predictive Science Academic Alliance Program. Purdue and its partners are contributing an additional $4.2 million.

The new centers will develop advanced science and engineering models and software for simulations needed to predict the reliability and durability of MEMS, machines that combine electronic and mechanical components on a microscopic scale. Researchers also will develop methods associated with the emerging disciplines of verification and validation and uncertainty quantification.

"The goal of these emerging disciplines is to enable scientists to make precise statements about the degree of confidence they have in their simulation-based predictions," Murthy said.

Under Prism, the MEMS devices will be created to replace conventional switches and other electronic components. MEMS are far lighter and smaller than the conventional technology and could be manufactured in large quantities at low cost, Murthy said. "Research is needed, however, to improve the reliability, ruggedness and durability of the devices," she said.

The simulations will make it possible to accurately predict how well the MEMS devices would stand up to the rigors of varying and extreme environments and how long they would last in the field, she said. Devices in many environments must withstand crushing gravitational forces, temperature extremes, radiation and shocks from impact.

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Jayathi Y. Murthy (standing), a professor in Purdue's School of Mechanical Engineering, works with graduate student Dipali Pradhan on a computer simulation to analyze how heat is transferred through a silicon nanowire. Murthy will lead a new center based at Purdue's Discovery Park to develop advanced simulations of microelectromechanical systems (MEMS) for commercial and defense applications. (Photo courtesy Purdue News Service/David Umberger)

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"Reliability pertains to long-term performance," Murthy said. "Improving the integrity and survivability relate to the fact that MEMS get used in very adverse conditions. You don't want the MEMS to fail before the systems in which they are embedded are deployed. MEMS have many potential important applications in civilian and defense applications."

For example, the switches can be used to turn radio signals on and off for a variety of purposes in national defense and for routing satellite communications. Potential civilian applications include cell phones and other telecommunications products, automotive sensors, and LCD projectors for large screens.

The technology will make it possible to reduce the size of switching equipment from several inches to 1 millimeter, or thousandth of a meter.

"Even though MEMS have a big size, weight and cost advantage, they are not really reliable enough yet," Murthy said.

A simulation system called MEMOSA will be created to model the specific types of MEMS switches used to turn radio frequency signals on and off. The tiny switches have a length of about 400 microns (millionths of a meter), or roughly four times the width of a human hair.

A challenge facing the researchers is creating "multiscale" simulations that bridge a broad range of size and time scales. They will aim to capture the entire workings of a design, from its nanometer-scale layout to its macro-scale features, as well as any failures that may occur in the MEMS over a time period that could range from billionths of a second to several months.

Creating the simulations will require the expertise of researchers from materials science, electrical engineering, mechanical engineering, aeronautics and astronautics, mathematics, computer science, and computer architecture. They will have access to unclassified supercomputers -- systems computing at the petascale level -- at the three NNSA national labs to run the large-scale simulations.

For more information, visit: www.purdue.edu/discoverypark/nanotechnology/