Germanium speeds transistor.

Germanium speeds transistor

Faster transistors can lead to faster, more powerful computers, which could make snappier bank transactions, more reliable weather predictions and more detailed simulations for research and product design. The silicon-based transistors shown at right can open and then close off a pathway of electrons as many as 75 billion times a second--a rate that nearly doubles the previous record and outpaces silicon transistors in today's mainframes by about sevenfold.

Germanium, a bigger chemical look-alike of silicon, is the key of making these "screaming-fast transistors," says Bernard S. Meyerson, who helped develop the devices at IBM's Thomas J. Watson-Research Center in Yorktown Heights, N.Y. The researchers used a technique called molecular beam epitaxy to control the proportion of germanium atoms in hundreds of successive atomic layers of silicon. The resulting germanium-silicon combination "is the equivalent of having a downhill slid across the base of the transistor, down which electrons can travel [faster]," Meyerson suggests. Other transistor makers have been unable to control the germanium content in silicon transistors with as much precision or without adding too many material defects for practical applications, he says.

The new transistors are raising eyebrows even among those who predic gallium arsenide will replace silicon in future computer chips, says Dirk J. Bartelink, who manages the new materials and structures group at Hewlett Packard Co. in Palo Alto, Calif.