Light-Emitting Silicon IP Company Spun-Out in U.K.

While silicon is not a natural emitter of light, many scientists and engineers have over the last decade investigated how nanometer-scale coatings, etchings and crystalline dislocations can be used to alter the material's bandgap to allow it to emit light.

The ability to convert electronic signals to, and from, optical signals could have great potential when available in the same material used for integrated circuits. Possible applications include on-chip optical interconnects, intrachip s ignaling, silicon optoelectronic ICs, MEMS and sensors. To achieve conventioanl electrooptical integration requires the use of hybrid systems based on compound semiconductor chips.

In October 2002, STMicroelectronics claimed it had developed light-emitting silicon, based on the implanting of ions of rare-earth metals such as erbium or cerium, in a layer of silicon rich oxide. The resulting silicon dioxide contained enriched silicon nanocrystals of one or two nanometers diameter.

Russell Gwilliam of the University of Surrey helped establish Si-Light Technologies, where he serves as chief executive officer and chief technology officer. The company hopes to exploit discoveries made at the university at about the same time that ST made it claims.

"A year ago we published in [the scientific journal] Nature on silicon dislocation loop engineering. We were able to show that dislocations put in the right place in relation to [electronic] junctions can overcome the problem of thermal quenching in silicon," Gwilliam said.

Thermal quenching means that although silicon can allow radiative electron-hole recombination at extremely low temperatures, nonradiative recombination processes dominate at room temperature.

Gwilliam said the government contract aims "to investigate the tuning of the emission wavelength to communications wavelengths of 1.3- and 1.5-nanometer."

The latest U.K. government funding will also be used to probe how to exploit the intellectual property commerically, and particularly how it could be incorporated into mainstream silicon in various applications, Gwilliam said.

"The business model is consultancy and IP licensing in some markets and fabless manufacturing in others," said Gwilliam. "For example, the technology could allow optical clocking of a microprocessor, but we wouldn't try to invent our own microprocessor. That would be a case for IP licensing."

Asked about venture funding or a partner with interests in opto-electronics, Gwilliam said a partner or p artners to develop a technology demonstrator was the first order of business.

The company's Web site is registered but not active.