ADVANCED MATERIALS & PROCESSES | JANUARY/FEBRUARY 2025 13 UNDERSTANDING DEGRADATION IN MICROELECTRONICS Researchers at the University of Minnesota Twin Cities, Minneapolis, gained new insights into how next-generation electronics, including memory components in computers, breakdown or degrade over time. Understanding the reasons for degradation could help improve efficiency of data storage solutions, which are increasing in demand as computing technology continues to rapidly advance. Spintronic magnetic tunnel junctions (MTJs)—nanostructured devices that use the spin of the electrons to improve hard drives, sensors, and other microelectronics systems, including magnetic random access memory (MRAM)—create promising alternatives for the next generation of memory devices. MTJs have been the building blocks for the nonvolatile memory in products like smart watches and in-memory computing with promise for applications to improve energy efficiency in AI. Using a sophisticated electron microscope, researchers looked at the nanopillars within these systems, and ran a current through the device to see how it operates. As researchers increased the current, they were able to observe how the device degrades and eventually dies in real time. They discovered that over time with a continuous current, the layers of the device get pinched and cause the device to malfunction. Previous work theorized this, but this is the first time researchers have been able to observe the phenomenon. Once the device forms a pinhole—the pinch—it’s in the early stages of degradation. As the researchers add more and more current to the device, it melts down and completely burns out. Looking more closely at the device at the atomic scale, researchers realized materials that small have very different properties, including melting temperatures. This means that the device will completely fail at a very different time frame than anyone has known before. “There has been a high demand to understand the interfaces between layers in real time under real working conditions, such as applying current and voltage, but no one has achieved this level of understanding before,” says researcher Jian-Ping Wang. twin-cities.umn.edu. TECHNIQUE TO MASS PRODUCE METAL NANOWIRES A new technique for growing tiny metal nanowires (NWs) for use in next-generation electronics was NANOTECHNOLOGY A pinhole’s degradation within a device is now observable. Courtesy of Mkhoyan Lab/University of Minnesota. developed by a group of researchers from Nagoya University in Japan. Their results suggest a way to mass produce pure metal NWs. The new method promises to enhance the efficiency of electronics production, including circuitry, LEDs, and solar cells. Until now, mass production of pure metal NWs has been challenging because of the difficulties of scaling production while maintaining quality and purity. NWs are so small that they are made by transporting atoms—typically in a gas phase state. However, this process is difficult to apply to metals, hindering the production of these important electronic components. To overcome this problem, the researchers used atomic diffusion in a solid phase state enhanced by ion beam irradiation to create aluminum NWs from single crystals. Using ion beams, the crystal grains were irradiated inside the thin aluminum film to coarsen them at the surface layer. This caused changes in stress distribution, guiding atomic flow, and was used as a means of supplying mass atomic feedstocks for NW growth to specific locations. In practice, when heat was applied, there was an upward flow of atoms through the gradient from the fine grains on the bottom to the coarse ones on top, resulting in mass growth of NWs. en.nagoya-u.ac.jp. Scientists at the DOE’s Pacific Northwest National Laboratory, Richland, Wash., achieved a uniform 2D layer of silk protein fragments on graphene. They say the discovery provides a reproducible method for silk protein self-assembly essential for designing and fabricating silk-based electronics. pnnl.gov. BRIEF Metal atom di usion leads to the growth of aluminum nanowires. Courtesy of Nagoya University.
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