February 09, 2007

AMO Manufactures First Graphene Transistors

The AMO nanoelectronics group of Dr. Max Lemme was able to manufacture top-gated transistor-like field-effect devices from monolayer graphene. A conventional CMOS-compatible process has been applied to fabricate a graphene field-effect device – a transistor made from a monolayer of carbon. The observed mobility in the devices exceeds the universal mobility in silicon MOSFETs. Furthermore, a second transistor gate was placed on top of the graphene film for the first time. AMO’s results confirm the high potential of graphene for future nanoelectronic devices.

Georgia Tech's Walt de Heer’s group had already made a few rudimentary graphene structures, including a graphene planar field-effect transistor in 2006.

A two-dimensional sheet of carbon, called graphene, has many of the same interesting properties as one-dimensional carbon nanotubes (CNTs). They conduct electricity with virtually no resistance. Graphene will provide a more controllable platform for integrated electronics than is possible with CNTs since graphene structures can be fabricated as large wafers using existing lithographic techniques. Continuous graphene circuitry can be produced using standard microelectronic processing techniques, which gives scientists a road map for high-volume graphene electronics manufacturing. De Heer’s team has managed to create feature sizes as small as 80 nm–well on the way towards their goal of 10 nm–using electron beam lithography. Electrons move with very little scattering through the resulting graphene circuitry. The researchers have also shown electronic coherence at near room temperature, as well as evidence of quantum interference effects. They expect to see ballistic transport when they make structures small enough.