|
The semiconductor industry has seen a remarkable miniaturization trend, driven by many scientific and technological innovations. But if this trend is to continue, and provide ever faster and cheaper computers, the size of microelectronic circuit components will soon need to reach the scale of atoms or molecules—a goal that will require conceptually new device structures. The field of molecular electronics seeks to use individual molecules to perform functions in electronic circuitry now performed by semiconductor devices. Individual molecules are hundreds of times smaller than the smallest features conceivably attainable by semiconductor technology. Electronic devices constructed from molecules will be hundreds of times smaller than their semiconductor-based counterparts. Moreover, individual molecules are easily made exactly the same by the billions and trillions. The dramatic reductions in size, and the sheer enormity of numbers in manufacture, are the principle benefits promised by the field of molecular electronics. Presently, our manufacturers manipulate millions and billions of atoms at a time using conventional technologies. They manipulate these atoms by pounding, chipping and other large scale mechanical deformation. They cook up pure silicon and then etch patterns on its surface. All these techniques depend on large scale manipulation of atoms. Manipulating atoms today is like trying to build houses out of Lego blocks using boxing gloves. You can push the Lego blocks together, but it's extremely difficult to make them snap together. In the future, molecular nanotechnology will allow us to take off the gloves and manipulate atoms directly. This will allow very complete control over the placement of individual atoms.
Often, nanotechnology is referred to as "bottom-up" manufacturing. It aims to start with the smallest possible building materials, atoms, and use them to create a desired product. Working with individual atoms allows the atom-by-atom design of structures. In most chemical reactions, unwanted byproducts are an inevitable consequence of the lack of control over the bonding reactions. With nanotechnology, unwanted byproducts can be essentially eliminated.
Nanotechnology should allow us to get essentially every atom in the right place, make almost any structure consistent with the laws of physics and chemistry that we can specify in atomic detail, and have manufacturing costs not greatly exceeding the cost of the required raw materials and energy.
Before nanotechnology can become anything other than a very impressive computer simulation, nanotechnologists must invent an assembler, a few-atoms-large nanomachine that will custom-build matter.
Engineers at Cornell and Stanford, as well as at Zyvex (the self-described "first molecular nanotechnology development company") are working to create such assemblers right now. But the obstacles are daunting. Unlike building with traditional materials that stay where you put them, atoms and molecules are volatile and will rearrange themselves Current and Emerging Electronic And Computer Technologies constantly to maintain stability. How far are we from having an assembler? Estimates vary. From 5 to 10 years, according to Zyvex,
or from 8 to 15 years, according to the research community. After that, it could
be decades before we'll be able to manufacture finished consumer goods. |
