Nano-sized step offers giant promise


Jun 26, 2006


Carbon Nanotube


This IC contains carbon nanotubes that are 50,000 times thinner than the human hair pictured.

Researchers at IBM have built the first complete electronic integrated circuit around one carbon nanotube molecule, a new material that shows promise for providing enhanced performance over today’s standard silicon semiconductors.


The circuit was built using standard semiconductor processes and used a single molecule as the base for all components in the circuit, rather than linking together individually-constructed components. This can simplify manufacturing, and provide the consistency needed to more thoroughly test and adjust the material for use in these applications.

“Carbon nanotube transistors have the potential to outperform state-of-the-art silicon devices,” says Dr. T.C. Chen, vice president, science & technology, IBM Research. “However, scientists have focused so far on fabricating and optimizing individual carbon nanotube transistors. Now, we can evaluate the potential of carbon nanotube electronics in complete circuits—a critical step toward the integration of the technology with existing chip-making techniques.”

For some 50 years, the semiconductor industry has packed increasing numbers of electronic circuits on a single silicon chip to make those chips more powerful. This was achieved largely by building circuits smaller. With scientists seeing an end to that capability looming, the use of nanotechnology is being explored as a means to keep the industry moving forward.

Nanotechnology involves the synthesis and assembly of new types of molecules and structures with dimensions measured in billionths of a meter. Looking like a microscopic roll of chicken wire, carbon nanotubes measure 50,000 times thinner than a human hair, but have unique properties that might allow them to carry higher current densities than the “pipes” currently used in today’s transistor and, with their smaller size, might allow for further miniaturization.

By integrating the complete circuit around a single nanotube, the IBM team observed circuit speeds nearly a million times faster than previously demonstrated circuits with multiple nanotubes. While this is still slower than the speeds obtained by today’s silicon chips, the IBM team believes that new nanofabrication processes will eventually unlock the superior performance potential of carbon nanotube electronics.