Silicon good to 2024, graphene to succeed
The ISSCC (International Solid State Circuit Conference) has started in San Francisco with keynote speaker James Meindl, professor of microelectronics at the Georgia Institute of Technology, making precise predictions about the future of silicon electronics and what will most likely follow in the post-silicon world.
'We will continue to scale vigorously for the next 15 years,'' he said, according to a report in EE Times. "Beyond silicon microchip technology, revolutionary developments in nanoelectronics, perhaps centering on graphene, may evolve.''
He said silicon could continue to scale to 7.9nm, due in 2024. Graphene, a novel form of carbon, could enable terascale computing (terahertz clock speed, terabyte memory) by then, or thereafter.
Graphene has been intensively studied for the past ten years, and recent breakthroughs in its manufacture and treatment seem set to overcome some of its disadvantages while making the most of its advantages over silicon. IBM recently demonstrated a 100GHz graphene transistor fabricated on a two-inch carbon wafer, which is faster than mainstream silicon transistors - although experimental silicon devices already run at over 60GHz. Researchers at the American Lawrence Berkeley National Laboratory have also found a way to induce a tunable bandgap in graphene, a necessary electronic state that allows the efficient switching necessary for workable transistors.
Meindl is quoted as giving six reasons why he thinks graphene will be the post-silicon technology of choice for electronics.
1. Graphene has the highest mechanical strength to weight ratio of any known material
2. Carrier mobility [the ease with which electrons can move through it] exceeds 200,000-cm2/Vs. [exceptionally high]
3. ''Carriers with zero effective mass that propagate as 'Dirac fermions' in a manner similar to photons with a velocity 300 times less than the speed of light without scattering for distances in the micrometer range.'' [also known as ballistic conduction, a form of energy transfer akin to superconductivity capable of great efficiency]
4. It can conduct currents one thousand times greater than can copper, without electromigration [a form of structural decomposition within a material due to large current flows]
5.Record values of room temperature thermal conductivity
6. Can serve as all parts of a transistor, as well as the interconnection between transistors
These seem like compelling arguments, especially when compared with the many limitations of potential rivals for the post-silicon world such as spintronics and quantum computing. The combination of the above reasons , together with graphene's ability to operate at room temperature, means that there is no theoretical reason - and ever fewer practical ones - why graphene can't be used to create extremely high performance electronic devices.