A Dash Of Germanium Adds Zip To Silicon Chips
Silicon has always been slower than gallium arsenide. That's why gallium arsenide is used for high-frequency chips in, for example, cellular phones. But that's about to change. IBM has pioneered a way of combining silicon with germanium that produces a tenfold speedup--to 1 billion cycles per second--in a chip from Analog Devices Inc. The secret? Sandwiching a region of germanium atoms into the silicon creates an electric slide of sorts that propels the electrons along their way.
Not only do the new chips consume less than a fifth of the power of gallium arsenide-based rivals, they will be cheaper to make, says IBM. That's because silicon-germanium chips can be made with the same equipment used for conventional chips. "We're leveraging $100 billion worth of installed equipment," says IBM Fellow Bernard S. Meyerson, who notes that Big Blue has cut its own gallium-arsenide research drastically. The unveiling of a working, 3,000-transistor part puts IBM ahead of such competitors as NEC, Daimler Benz, and Texas Instruments, which have just gotten around to showing single circuits made of the material.