|
India
Telecom
August 5, 2003
STMicroelectronics sets world record
NEW DELHI -- STMicroelectronics, recently announced
details of a ground-breaking technology that allows
silicon-based light emitters to match the efficiency
of traditional light-emitting compound semiconductor
materials such as gallium arsenide (GaAs). The new technology
opens several potential applications in which optical
and electrical functions are combined on a single silicon
chip. This was not previously possible, as although
silicon is ideal for building memories, microprocessors
and other complex circuits, it could not be made to
act as an efficient light emitter.
Developed
in Catania, Sicily, by researchers from ST's corporate
technology R&D organization, one of the first applications
of the new technology is to build power control devices
in which the control circuitry is electrically isolated
from the power switching transistors. Currently, electrical
isolation that is mandatory in many applications for
safety reasons, can only be achieved by using external
devices such as relays, transformers or discrete optocouplers,
all of which involve additional cost, power consumption
or bulk.
Based
on an innovative structure in which ions of rare-earth
metals such as erbium or cerium are implanted in a layer
of silicon-rich oxide (SRO), the frequency of the emitted
light depends on the choice of rare-earth dopant. ST
has patented key techniques for implanting the rare-earth
ions into the silicon.
ST
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. These devices will have numerous important
applications, including motor control, power supplies,
solid-state relays and similar applications where the
power circuit needs to handle much higher voltages than
the control circuit.
In
the longer term, ST is investigating integrated optical
data-transmission systems for use in advanced CMOS circuits
where clock signals are distributed through the chip
at the speed of light, as well as low-cost integrated
devices for DWDM fiber-optic communication.
Contact:
STMicroelectronics
www.st.com
|
