CARBON TO BE IN COMPUTERS
An Indian researcher, Subhasish Mitra, is leading the race to find an alternative to silicon chips in carbon
It will be 50 years this April, since Gordon Moore made his famous projection that the number of transistors in a silicon chip would double every two years or so. When Intel made the world’s first integrated circuit, it had 2,300 transistors. The latest Core i7 chip, has more than a billion. With time, each transistor shrank in size, it is now around 20 nanometers. If Moore’s Law holds true, technology will shrink the transistor to 14 NM at the end of this year and 10 NM, three years hence. But around 2020, scientists say, the silicon saga will end.
The most promising next option seems to be carbon or rather its purest form, called graphene. Roll up a very thin sheet of graphene, then chop it into tiny pieces called carbon nano tubes, that is a great conductor of electricity where signals move 10 times faster than through silicon. And here’s the bonus, very little energy is lost.
And the team that is closest world-wide to actually producing a carbon nano tube computer, is led by an Indian. Kolkata-bred, Jadavpur University, IIT Kharagpur and Stanford University (US)-educated, Subhasish Mitra. Currently, he is the Associate Professor of Electrical Engineering and of Computer Science at Stanford.
His team had already demonstrated the carbon computer two years ago. Composed of 178 transistors, each containing between 10 and 200 carbon nano tubes, it ran simple tasks and was hailed as a “true milestone in the fields of carbon-and-nano electronics”. But the real task lay ahead — how to ensure that the carbon nano tube could be fabricated in millions to the same accuracy so that the computers could be scaled up to real power. Last month, this test too was passed — as Prof Mitra told IndiaTechOnline in a special briefing on the sidelines of a VLSI conference in Bengaluru. The process established at Stanford’s Nano Fabrication Facility, was scalable for real world manufacture.
The Mitra-led team has also cracked another problem. How to get the memory part of a computer to co-exist with the computing part on the same chip. They accomplished this by applying the principle of a BigMac burger — place alternate layers of logic and memory on top of each other to form the world’s first ‘high-rise’ chip. “Our design and fabrication techniques are scalable,” says Mitra “With further development this architecture could lead to computing performance that is much greater than anything available today.”
His team is the closest to producing a carbon nano tube computer