Carbon nanotube transistor channels are so small--a single nanometer thick--that heat has a hard time transferring to a nanotube substrate. The gap between nanotube and its silicon oxide substrate thermally insulates the nanotube, meaning heat builds up in the structure rather than dissipating. IBM researchers claim to have found a possible means of cooling carbon-based transistors by directly coupling their electric current fields with those of a silicon substrate. Solving a heat-dissipation problem brings carbon-based transistors one step closer to commercialization, they said. (click story title for full text).
BOTTOM LINE: Carbon-based transistors--either using nanotubes or flattened out sheets of graphene--promise to accelerate electronics with the faster operation of so-called ballistic transport mechanisms. However, integrating carbon into the semiconductor fabrication process, alongside current silicon materials, is a daunting task. One problem, dissipating heat from carbon which does not chemically bond well to silicon, has plagued device designers, but may now be solved by IBM. The verdict is still being formulated, but if thermally coupling can be accomplished with electric fields, as IBM suggests, then one crippling obstacle to commercialization will be surmounted. Look for carbon-transistors to appear in commercial chips within five to ten years.
