March 24, 2006 – IBM Corp. has built the first complete electronic IC around a single carbon nanotube molecule using standard semiconductor processes, an achievement that could simplify future manufacturing and consistency of such devices vs. creating them by linking individually constructed components.
Scientists from IBM, the U. of Florida, and Columbia U. built a five-stage ring oscillator with 12 FETs side by side along the length of an individual carbon nanotube, creating a complementary metal-oxide semiconductor (CMOS)-type architecture by adjusting the gate work functions of the individual p-type and n-type FETs. Circuit speeds were observed at nearly a million times faster than previously demonstrated circuits with multiple nanotubes, although still slower than today’s silicon chips.
“Single-walled carbon nanotubes have been shown to exhibit excellent electrical properties, such as ballistic transport over several hundred nanometers at room temperature,” noted IBM, in an abstract from the report. “Field-effect transistors (FETs) made from individual tubes show DC performance specifications rivaling those of state-of-the-art silicon devices.”
The researchers noted that the next step is to fabricate ICs on single-walled carbon nanotubes to study their high-frequency AC capabilities. Results of IBM’s research are published in the March 24 issue of the journal Science.