The success of many advanced technologies that use devices such as sensors and actuators, including gyroscopes and optical devices, depends on microscopic components called microelectromechanical systems (MEMS) devices made of polycrystalline silicon (polysilicon). Researchers at Case Western Reserve University report in the November 8 issue of Science that miniature micron-sized polysilicon laboratory specimens subjected to cyclic tension/compression loading undergo fatigue, and could ultimately fail as a result of damage produced by the compressive cycles, rather than from moisture-assisted stress corrosion cracking. This information, they say, could assist MEMS developers to mitigate fatigue failure in MEMS devices that experience significant mechanical stress during operation.
The Science article ("Fatigue Failure in Polysilicon: It’s Not Due to Simple Stress Corrosion Cracking") was written by Harold Kahn, Research Associate Professor in the department of materials science and engineering; Roberto Ballarini, Professor in the department of civil engineering and a lead researcher on the project; Arthur Heuer, University Professor and Kyocera Professor of Ceramics in the department of materials science and engineering; and Justin Bellante, a recent BS/MS graduate of materials science and engineering.
Polysilicon, CWRU researchers say, is a manufactured thin film consisting of silicon crystallites that is made in a microfabrication laboratory using chemical vapor deposition. The films are associated with rough surfaces that result from the plasma etching used in the final stages of MEMS processing. The researchers speculate that under compressive loading, these surfaces come into contact, and their wedging action produces microcracks that grow during subsequent tension and compression cycles.
Marci E. Hersh | EurekAlert!
First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D
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Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.
Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...
Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.
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The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
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With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
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