Silicon fibre technology development for wearable and ambient electronics applications

The concept of silicon fibre technology follows the aspiration of making whole computers recede into textile format, which can be used in a wearable or ambient environment. The integration of IC technology into fibre format is an important development for a wide range of emerging scientific applications from wearable vital sign health monitoring systems [1] to Ambient Intelligence Microsystems. This concept is achieved by building a device in silicon on insulator (SOI) [2] material and undercutting the sacrificial SiO₂ layer by a combination of isotropic and anisotropic etch processes, to leave a freestanding functional fibre. A demonstration of functionality based on this technology was produced in the form of a PN diode on a fibre [3]. After demonstrating the feasibility of the concept, subsequent active device circuits were designed and fabricated as a more complex demonstration of functionality. One of the primary considerations involved with this technology is the interconnection of these flexible silicon structures to each other and to the outside environment. A novel interconnection protocol has been developed and a prototype demonstration of a flexible LED circuit has been fabricated.