Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.
Stretchable and foldable silicon-based electronics
A. C. Cavazos Sepulveda, M. S. Diaz Cordero, A. A. A. Carreño, J. M. Nassar, M. M. Hussain; Stretchable and foldable silicon-based electronics. Appl. Phys. Lett. 27 March 2017; 110 (13): 134103. https://doi.org/10.1063/1.4979545
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