Microchip miniaturisation barrier could be broken by nanotechnology

10 July 2006

A project that could remove the electrical wiring in microchips, allowing denser circuitry, could result in computers with 500 times the power of present day technology. The University of Bath is to lead an international £555,000 three-year project to develop the wireless silicon chip system.

As microchip circuits are made smaller to increase processing power they approach a limit imposed by the need to use electric wiring, which weakens signals sent between computer components at high speed. Wireless systems are in widespread use in mobile phones, Bluetooth gadgets, Wi-fi computers etc, but the electronics that create and use wireless signals are too large to be used within individual microchips successfully.

The research project, which involves four universities in the UK and a university and research centre in Belgium and France, will look at ways of producing microwave energy on a small scale by firing electrons into magnetic fields produced in semi-conductors that are only a few atoms wide and are layered with magnets.

The process, called inverse electron spin resonance, uses the magnetic field to deflect electrons and to modify their magnetic direction. This creates oscillations of the electrons which makes them produce microwave energy. This can then be used to broadcast electric signals in free space without the weakening caused by wires.

The possibility of using the special semi-conductors in this way was first pointed out by Dr Alain Nogaret, of the University of Bath’s Department of Physics, in an important scientific paper in 2005 (Electrically induced Raman Emission from planar spin oscillator, in Physical Review Letters). The latest research is the first attempt to turn theory into practice.

“The work could be very important for the creation of faster, more powerful computers,” said Dr Nogaret. “We can only go so far in getting more power from silicon chips by shrinking their components — conventional technology is already reaching the physical limits of materials it uses, such as copper wiring, and its evolution will come to a halt.

“But if this research is successful, it could make computers with wireless semi-conductors a possibility within five or ten years of the end of the project. Then computers could be made anything from 200 to 500 times quicker and still be the same size.

“This research may also improve the accuracy and speed of medical diagnostics by gathering data from health monitoring sensors. The microwave emitters are small enough to be integrated on portable biological sensors which feed information out on faulty biological processes.

“The research is not only practical, but beautiful in its theoretical simplicity, which is one of the big attractions for the physicists working on it.”

The project is the only one which aims to create wireless emitters and receivers that fit on semi-conductor wafers, where individual devices are one ten thousandth of a millimetre in size.

It will also allow the creation of integrated circuits which will still continue to work properly even if some of its connections fail —the system can be programmed to reroute itself so that it can continue working. At present a failure in a connecting wire can put an integrated circuit out of action.

In the manufacture of today’s integrated circuits there is no room for error, and so manufacturers must spend large amounts of money to build dust-free clean rooms. The advantage of the new more flexible system is that only 95% or so of the electronic components would need to work for the chip to work properly. Such chips would be many times cheaper to produce.

Dr Nogaret is working with colleagues Professor Simon Bending and Professor John Davies in the University’s £2m laboratory dedicated to nanotechnology.

The University receives £463,000 for the project, which begins in October. The University of Nottingham receives £65,000, and the University of Leeds £27,000, all from the Engineering and Physical Sciences Research Council. The University of St Andrews in Scotland, and the University of Antwerp, Belgium, will also take part, as will the Centre National de la Recherche Scientifique in Grenoble, France.

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