The quantum-effect device: Tomorrow's transistors

There are limits on the size and number of circuit elements that can be packed on a computer chip. One is the wave behavior of electrons, which can interfere with performance in the smallest of devices. Physicists are not turning that behavior to their advantage in a new kind of component that depends on electron waves for its operation. With the so called quantum semiconductor device, it will be possible to put the circuitry of a supercomputer on a single chip. The structures for quantum devices have already been made using the same materials as today's chips. Because they can be about 100 times smaller than the devices in present-day integrated circuits, designing and fabricating a viable device presents a formidable challenge. Manufacturing processes will have to become considerably more sophisticated, and new strategies for interconnection and architecture will have to be devised to cope with the special problems of size reduction. 5 figs.