Saturday, September 06, 2003
Reinventing the Transistor
Claire Tristram writes in the September issue of Techology Review about blue skies research being conducted at HP to build computers whose functionality depends on the working of individual molecules.
To do so will mean reinventing the transistor. While silicon and other inorganic semiconductors have always been the basic building blocks of microchips, it turns out that organic molecules can also have some potentially useful electrical properties. Indeed, over the last few years, researchers have learned to synthesize molecules that can function as electronic switches, holding binary 1s or 0s in memory or taking part in logical operations. And molecules have one significant advantage: they are really small.
Such work is critical to the future of computing, because conventional chip fabrication technology is on a collision course with economics. Today’s best computer chips have silicon features as small as 90 nanometers. But the smaller the features, the more expensive the optical equipment needed to manufacture them. A state-of-the-art fabrication plant for silicon microchips now costs some $3 billion to build. A chip in which silicon transistors are replaced with molecular devices, on the other hand, could in principle be fabricated through a simple chemical process as inexpensive as making photographic film. A circuit with 10 billion switches could eventually fit on a grain of salt; that’s a thousand times the density of the transistors in today’s best computers.
To do so will mean reinventing the transistor. While silicon and other inorganic semiconductors have always been the basic building blocks of microchips, it turns out that organic molecules can also have some potentially useful electrical properties. Indeed, over the last few years, researchers have learned to synthesize molecules that can function as electronic switches, holding binary 1s or 0s in memory or taking part in logical operations. And molecules have one significant advantage: they are really small.
Such work is critical to the future of computing, because conventional chip fabrication technology is on a collision course with economics. Today’s best computer chips have silicon features as small as 90 nanometers. But the smaller the features, the more expensive the optical equipment needed to manufacture them. A state-of-the-art fabrication plant for silicon microchips now costs some $3 billion to build. A chip in which silicon transistors are replaced with molecular devices, on the other hand, could in principle be fabricated through a simple chemical process as inexpensive as making photographic film. A circuit with 10 billion switches could eventually fit on a grain of salt; that’s a thousand times the density of the transistors in today’s best computers.
