Researchers have developed a form of single-crystal silicon that can be stretched so that electronic circuits could be fabricated on rubber. To prove the concept, professor John Rogers, a materials scientist at at the University of Illinois at Urbana-Chamapign, and his colleagues made diodes and transistors that matched the performance or rigid devices, but "could be repeatedly stretched and compressed without damage." From a press release:
Functional, stretchable and bendable electronics could be used in applications such as sensors and drive electronics for integration into artificial muscles or biological tissues, structural monitors wrapped around aircraft wings, and conformable skins for integrated robotic sensors, said Rogers...Link
To create their stretchable silicon, the researchers begin by fabricating devices in the geometry of ultrathin ribbons on a silicon wafer using procedures similar to those used in conventional electronics. Then they use specialized etching techniques to undercut the devices. The resulting ribbons of silicon are about 100 nanometers thick – 1,000 times smaller than the diameter of a human hair.
In the next step, a flat rubber substrate is stretched and placed on top of the ribbons. Peeling the rubber away lifts the ribbons off the wafer and leaves them adhered to the rubber surface. Releasing the stress in the rubber causes the silicon ribbons and the rubber to buckle into a series of well-defined waves that resemble an accordion.