Silicon germanium (SiGe)

As the circuitry on chips was continually scaled down to achieve greater speeds, it became clear that the performance characteristics of bipolar silicon chips would eventually break down at very tiny dimensions. If bipolar silicon was to continue to advance in speed, an alternative technology was needed.

IBM's answer was silicon germanium, a compound which, it was hoped, would permit device designers to simultaneously increase speed, reduce electronic noise, and lower power supply requirements.

Silicon germanium technology holds great promise for reducing the cost of consumer products (cellular telephones and direct broadcast satellite entertainment services), improving business applications (telephone network transmission), and helping make possible new applications (collision-avoidance automobile radar). Silicon germanium also might be used in products that consumers use, but never see, such as the driver chips that turn lasers on and off inside fiber-optic telephone lines.