Feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...

-controlled electromigration (FCE) is an experimental technique to investigate the phenomenon known as

electromigration Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is important in applications where high direc ...

. By controlling the voltage applied as the conductance varies it is possible to keep the voltage at a critical level for

Theory

FCE has been shown to be reversible, demonstrating the fact that the electrons are moving rather than thermomigration or

sublimation Sublimation or sublimate may refer to: * ''Sublimation'' (album), by Canvas Solaris, 2004 * Sublimation (phase transition), directly from the solid to the gas phase * Sublimation (psychology), a mature type of defense mechanism * Sublimate of mer ...

. The migration occurs due to the electronic wind force experienced by the metallic adatom. The electromigration occurs at a critical power dissipation

P=I/G

in the neck of the bridge. This leads to Electromigrated Nanogaps.

Uses

FCE is often used in forming nanogaps in metallic bridges.

Problems

Thermal runaway can occur when the neck is narrower than about 20 nm.

References and external links

{{reflist, 2 Electronic design automation Semiconductor device defects Nanoelectronics Emerging technologies