Stretchable electronics: new process simplifies production of functional prototypes

With their new method, the researchers produced three prototypes, each taking less than five minutes. @ Saarland University

Technical systems and devices such as computers, cell phones, airplanes and cars are all controlled by microelectronics based on the electric charge of particles. However, these electronic components are sensitive because a complex circuit is needed for the flow of charged electrons. In many cases this could be greatly simplified if one could instead use another property of electrons: the electron spin. This momentum of an electron is an invariable quantity, so that it could just as reliably serve as an information store. Scientists led by Professor Uwe Hartmann from Saarland University want to develop cost-effective microelectronics based on this basic principle.

If one opens today any technical product, be it a mobile phone, a computer or an airplane, one often looks similar: The electronics under the covers and panels. Green boards on which circuits are connected, over which positively or negatively charged particles fly back and forth, transporting information from A to B. These particles translate users' commands into action, such as "Call Mutti" or "Initiate Descent". This electronic basic principle is common to all technical devices today. They all work on the principle that electricity flows from A to B.

Although it is now possible to maintain this property for many years or even decades. But after a while, the flow of electrons weakens. On a long-unused USB stick, for example, this is expressed by information being lost.

Things behave differently, working with the principle of the electron spin, which can be thought of as a kind of fixed angular momentum of an electron. The electron rotates like a table tennis ball or as the rotation of the earth, but without the angular momentum becoming weaker as in the examples mentioned above. "The spin can be maintained over very long periods," explains Uwe Hartmann, experimental physicist and professor of nanostructure research and nanotechnology at the University of Saarland. He is also significantly less sensitive to external influences. "For example, an airplane that flies at ten kilometers altitude has to be screened against strong ionizing radiation at that altitude so that its electronics do not fail," explains the physicist.

In order to further understand the basics of such spintronic components and to develop a sensor prototype, the working groups of several German universities and industrial companies have now joined forces. In the program "Research for new microelectronics (ForMikro)" of the Federal Ministry of Research, the consortium, which is coordinated by Uwe Hartmann, since October 2019 with approximately 1.6 million euros funded, of which 740,000 euros flow to the University of Saarland.

Although there are already spintronic components, for example, highly sensitive sensors. However, these currently cost well over $ 100 a piece and are therefore not suitable for mass use. The reason is complicated microwave electronics needed to operate the sensors. "For the first time, we want to build an integrated circuit of different elements that does not need any complicated switching electronics. Our goal is a prototype that only needs a small battery to function, "says Uwe Hartmann, explaining the goal of the research network, which will be funded by September 2023. Later, such spintronic components could be suitable for widespread use in everyday technology, for example as low-cost sensors in mobile phones,

Also for future technologies the spintronic components could be helpful. For all known theoretical concepts and laboratory experiences: "Someone has to build the electronics of the future in the form of mass-produced products", Uwe Hartmann states pragmatically. And while the Asians and the Americans in semiconductor technology currently have a big lead, because Europe missed the connection here. With advances in spintronics, however, the tide could turn again. "Then the cards are shuffled," predicts Hartmann.

The project "Research of novel magnetic sensors based on spintronic effects"is funded with 1.6 million euros for four years as part of the BMBF Research for New Microelectronics (ForMikro) program. In addition to the University of Saarland, University of Halle-Wittenberg, Bielefeld University, Sensitec GmbH, Singulus Technologies AG, SENSYS GmbH are also involved.

LASEC: Instant Fabrication of Stretchable Circuits Using a Laser Cutter

Daniel Groeger and Jürgen Steimle

CHI 2019, May 4–9, 2019, Glasgow, Scotland UK

DOI: 10.1145/3290605.3300929

Contact information:

Prof. Dr. med. Uwe Hartmann

Phone: (0681) 302-3799/3798

Nanostructural Research and Nanotechnology group

Saarland University




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