What will replace silicon?

Eventually the doubling and redoubling of computer power that has driven the information age will cease. Then what?

The economic destiny and prosperity of entire nations may rest on one question: Can silicon-based computer technology sustain Moore’s law beyond 2020? The secret behind Moore’s law is that chipmakers double every 18 months or so the number of transistors that can be crammed onto a silicon wafer the size of a fingernail. They do this by etching mi­croscopic grooves onto crystalline silicon with beams of ultraviolet radiation. A typical wire in a Pentium chip is now 1/500 the width of a human hair; the insulating layer is only 25 atoms thick.

But the laws of physics suggest that this doubling cannot be sustained forever. Eventually transistors will become so tiny that their silicon components will approach the size of molecules. At these incredibly tiny distances, the bizarre rules of quantum me­chanics take over, permitting electrons to jump from one place to another without passing through the space between. Like water from a leaky fire hose, electrons will spurt across atom-size wires and insulators, causing fatal short circuits.

Transistor components are fast approaching the dreaded point-one limit – when the width of transistor components reaches 1 micron and their insulating layers are only a few atoms thick. Among physicists, the race to create the Silicon Valley for the next century has already begun. Some of theoretical options being explored:

§ THE OPTICAL COMPUTER This computer replaces electricity with laser light beams. Unlike wires, light beams pass through one another, making possible three-dimensional microprocessors. An optical transistor has already been vented; unfortunately, the components are still rather large and clumsy. The optical counterpart of a desktop computer would be the size of a car.

§ THE DNA COMPUTER One of the most ingenious ideas being pursued is to compute using DNA, treating the double-stranded molecule as a kind of biological computer tape (except that instead of encoding 0s and 1s in binary, it uses the four nucleic acids, represented by A, T, C, G). This approach holds much promise for crunching big numbers. Hence large banks and institutions may one day use it. However, a DNA computer is an unwieldy contraption, consisting of a jungle of tubes of organic liquid, and is unlikely to replace a laptop in the future.

§ MOLECULAR AND DOT COMPUTERS Other exotic design include the molecular computer and the quantum dot computer (which replace the silicon transistor with a single molecule and a single electron, respectively). But these approaches face formidable technical problems, such as mass-producing atomic wires and insulators. No viable prototypes yet exist.

§ THE QUANTUM COMPUTER The darkest horse to emerge in this race is the quantum computer, sometimes dubbed the ultimate computer. The idea is to direct a laser or radio beam on a carefully arranged collection of atomic nuclei, each of which is spinning like a top. As the beam bounces off the atoms, it flips the spins of some of them. Complex computations can be performed by analyzing how the spins have been flipped.

Clearly, none of these designs are ready for prime time. Most are still on the drawing board, and even those with working proto­types are too crude to rival the convenience and efficiency of silicon.

IV. Translate the following word combinations from Russian into English:

Лазерные световые лучи; в отличие от проводов; трёхмерные микропроцессоры; биологическая компьютерная лента; заменить лэптоп; значительные технические проблемы; массовое производство; вращение.

V. Complete the phrases with prepositions and use them in sentences of your own:

1) to etch mi­croscopic grooves … crystalline silicon … beams … ultraviolet radiation;

2) A Pentium chip is now 1/500 the width … a human hair;

3) to permit electrons to jump … one place … another … passing through the space between;

4) to replace electricity … laser light beams;

5) to direct a laser or radio beam … a carefully arranged collection … atomic nuclei;

6) convenience and efficiency … silicon

VI. Answer the following questions:

1) How do chipmakers double the number of transistors that can be crammed onto a silicon wafer?

2) Why cannot this doubling be sustained forever?

3) An optical transistor has already been invented, hasn’t it?

4) What is the main drawback of the DNA computer?

5) Do molecular & DOT computers face formidable technical problems? What are they?

6) What can be performed by analyzing how spins have been flipped?

VII. Complete the parts of the chart, using the text and your own ideas:

	Theoretical options	« + »	« - »	Your opinion
1.	Optical computer
2.	DNA computer
3.	Molecular and DOT computer
4.	Quantum computer

VIII. Read the following text and analyze it: