The majority of flexible electronics that are manufactured at present are based on polymer substances; however, these polymers have substandard semiconducting properties in comparison to silicon. Further, in contrast to silicon, many polymers are not completely attuned with the standard fabrication procedures utilized in semiconductor industries at present.
If silicon is shown to be mechanically strong enough to undergo the bending and stretching needed by flexible electronics, it will potentially provide a perfect substance for making commercial flexible electronics on a huge scale.
A research team at the King Abdullah University of Science and Technology has developed a technique for producing silicon-based electronics that can be folded and stretched without damage, avoiding the issue of excessive fragility that is faced by the ultra-thin flexible silicon substances. In order to achieve this, the team devised a silicon-based tool consisting of silicon islands interlinked by slim, stretchy silicon springs. Mechanical support is offered by the thick island, whereas flexibility is offered by the thin springs.
Designing the microscale in a way that would avoid them from intertwining with each other, at the same time also enable them to expand several times their actual length was the biggest challenge faced by the team. Even though the team thought of fractal patterns and spiral shapes, the best pattern that they came up with was motivated by imitating the spherulite-lamellar motif of nature, a design that looks like the radiating lines observed in rocks. Trials demonstrated that this geometrical pattern has the benefit of scattering the bending-stimulated strain over the complete length of the spring.
The final tool can be extended to more than 5 times its actual area owing to the stretchable springs. The springs also enable the islands to crease on top of each other. As these new patterning processes are well-suited to the present semiconductor fabrication techniques, the team anticipates that the pattern can be utilized to manufacture a broad array of flexible equipment. The possible applications consist of solar cells that adapt to curved surfaces, 3-D stacking of integrated circuits, wearable electronics, and tangible displays that fold similar to origami.