STMicroelectronics Discovers Silicon Light Breakthrough

June 12, 2005 by Jeff Shepard

STMicroelectronics Inc. (ST, Geneva, Switzerland) announced that it has discovered ground-breaking technology that allows silicon-based light emitters to match the efficiency of traditional light-emitting compound semiconductor materials such as gallium arsenide. The origins of the new technology, which sets a world record for quantum efficiency, are linked to important Air Force Research Laboratory (AFRL)-sponsored studies conducted jointly with the laboratory and the Massachusetts Institute of Technology.

The new technology is based on a structure where researchers implant ions of rare earth metals in a layer of silicon-rich oxide. The technology opens up many potential applications in which optical and electrical functions reside on a single silicon chip. Although silicon is ideal for building computer memory, microprocessors and other complex circuits, it is not an efficient light emitter. One of the first applications of the new technology will be to build power control devices in which the control circuitry is electrically isolated from the power switching transistors.

"The ability to combine optical and electronic processing on the same chip presents enormous opportunities," stated STMicroelectronics Corporate Technology Research and Development Director Gian Guido Rizzotto. "We have identified a number of promising applications, and key manufacturing issues have already been solved so the technology can be rapidly moved into production."

In an extension of the technology, STMicroelectronics has patented a novel structure in which two circuits, built on the same chip, but electrically separated from each other by insulating silicon dioxide, communicate via optical signals using integrated silicon light emitters and detectors. Devices based on this design will have a number of important uses, including motor controls, power supplies, solid-state relays and similar applications in which the power circuit operates at much higher voltages than the control circuit.