Carbon nanotube transistors are a step closer to commercial reality, now that MIT researchers have demonstrated that the devices can be made swiftly in commercial facilities, with the same equipment used to manufacture the silicon-based transistors that are the backbone of today’s computing industry.
Carbon nanotube field-effect transistors or CNFETs are more energy-efficient than silicon field-effect transistors and could be used to build new types of three-dimensional microprocessors. But until now, they’ve existed mostly in an “artisanal” space, crafted in small quantities in academic laboratories.
In a study published in the journal Nature Electronics, however, scientists show how CNFETs can be fabricated in large quantities on 200-millimeter wafers that are the industry standard in computer chip design. The CNFETs were created in a commercial silicon manufacturing facility and a semiconductor foundry in the United States.
After analyzing the deposition technique used to make the CNFETs, the MIT researchers made some changes to speed up the fabrication process by more than 1,100 times compared to the conventional method, while also reducing the cost of production. The technique deposited carbon nanotubes edge to edge on the wafers, with 14,400 by 14,400 arrays CFNETs distributed across multiple wafers.
For decades, improvements in silicon-based transistor manufacturing have brought down prices and increased energy efficiency in computing. That trend may be nearing its end, however, as increasing numbers of transistors packed into integrated circuits do not appear to be increasing energy efficiency at historic rates.
CNFETs are an attractive alternative technology because they are “around an order of magnitude more energy efficient” than silicon-based transistors.
Unlike silicon-based transistors, which are made at temperatures around 450 to 500 degrees Celsius, CNFETs also can be manufactured at near-room temperatures. This means that we can actually build layers of circuits right on top of previously fabricated layers of circuits, to create a three-dimensional chip. we can’t do this with silicon-based technology, because we would melt the layers underneath.
A 3D computer chip, which might combine logic and memory functions, is projected to “beat the performance of a state-of-the-art 2D chip made from silicon by orders of magnitude.
News Source: MIT
