Date: 13th Jun 2011

Graphene based IC chips; the next imminent trend in semiconductor tech

IBM researchers have developed first integrated-circuit fabricated from wafer-size Graphene where a RF mixer operating at the frequencies up to 10 GHz is integrated in the circuit. This 10 GHz frequency capability in a single chip can enable wireless devices handle superior bandwidth compared to the present silicon based semiconductor devices. This technology can also enable defense electronics to scan objects for more hidden things using simple handheld devices, be emitting safer radiation.

IBM has created the Graphene by thermal annealing processing of silicon carbide (SiC) to high temperatures resulting in the production of epitaxial Graphene. Graphene based transistor circuits are fabricated by IBM using four metal layers and two oxide layers. The integrated circuit also has on-chip inductors and interconnects. The RF electronic components inside this chip shown a thermal stability up to 125 Deg C.

IBM's lead in the Graphene material based nanotechnology research indicates Graphene is fast emerging as a replacement of silicon as major semiconductor material. Graphene is a variance of pure carbon materil Graphite. In a one atom thick foil like Graphene sheet, the carbon atoms are densely packed in a honeycomb like crystal lattice. The crystalline or "flake" form of graphite consists of many Graphene sheets stacked together. See the image below.

         

The challenge today for semiconductor researchers is putting Graphene and other silicon and non-silicon based devices together on a single chip and also make use of present lithography based semiconductor equipment and the processes.

IBM looks to have taken important lead in this, the new integrated circuit fabricated by IBM is made up of Graphene transistor and a pair of inductors compactly integrated on a silicon carbide (SiC) wafer and is developed using wafer-scale fabrication procedures that maintain the quality of Graphene and, at the same time, allow for its integration to other components in a complex circuitry.

IBM defines this tech-breakthrough is a major milestone for the Carbon Electronics for RF Applica-tions (CERA) program, funded by DARPA.

IBM says the fabrication scheme developed can also be applied to other types of Graphene materials, including chemical vapor deposited (CVD) Graphene films synthesized on metal films, and are also compatible with optical lithography for reduced cost and throughput.

IBM has earlier demonstrated standalone Graphene transistors with a cut-off frequency of 100 GHz and 155 GHz for epitaxial and CVD Graphene, for a gate length of 240 and 40 nm, respectively.