Currently, Intel's smallest silicon transistor measures 14 nanometers. That's very small. It is not, however, small enough for innovation to keep up with Moore's Law which says that the number of transistors that fit on a circuit should double every year (or so). Moore's Law is how IBM pegged the commercialization of carbon nanotube transistors to 2020, when the company says chips made out of nanotubes as small as five nanometers will be available. "That's where silicon scaling runs out of steam, and there really is nothing else," says Wilfried Haensch, the head of IBM's carbon nanotube program.