Some day you may see a workman replacing a location sign designating Silicon Valley. In its place the new sign could read Nanotube Valley, or maybe Graphene Gulch. That is improbable at best, but could be more accurate. Researchers are anticipating the day when it will be impossible to further miniaturize silicon transistors, and are developing alternative materials.
Candidates currently being explored in labs are gallium arsenide, graphene, and carbon nanotubes. Engineers hope that transistors made from these materials will be smaller, faster, and more energy efficient than silicon.
The MIT Technology Review commented, “It’s still uncertain what will ultimately replace silicon. But this once dominant material is already looking too fragile, too power hungry, and too expensive to drive our computers forever.”
Michael Mayberry, director of components research at Intel, says,”We need to add more materials to the tool box.” Intel has developed expertise in compound semiconductors, such as gallium arsenide. IBM has made transistors from graphene. At Stanford work is going forward on cylindrical molecules of carbon.
One challenge, according to the MIT Review is to make new materials work with the infrastructure built for silicon, which represents billions of dollars in investment for chip makers and their huge fabrication plants.
Silicon makes up about 25% of the Earth’s crust and is the second most abundant element in the crust after oxygen. It is widely used in semiconductors, most importantly integrated circuits or microchips. It is also an essential element in biology, but only tiny traces of it appear to be required by animals.
