The miniaturisation of electronic devices has been an ongoing trend in the electronics industry, but further developments are challenged by the size of transistors.
While transistors have certainly reduced in size significantly, researchers in recent years have been unable to shrink them any further. This is because any such attempt failed to circumvent the problem of overheating, which becomes more acute in smaller transistors.
Overheating is caused by the huge amount of energy released by the movement of electrons. Researchers have hitherto been unable to reduce the dissipation of heat in conventional semiconductor materials such as silicon. Using transistors in wireless chipsets operating at high frequencies such as the 60 GHz band also causes problems due to overheating and reduces the potential to exploit such frequencies for novel applications.
Researchers have now been able to develop a new type of transistor, using nanotechnology, which is said to be 50 times more energy efficient than contemporary models. This new model is made up of indium arsenide (InAs), in which electrons can move around more easily than silicon.
In a paper published in the Institute of Electrical and Electronics Engineers’ Electron Device Letters journal, the researchers from Sweden-based Lund University, presented the results on the fabrication of vertical InAs nanowire wrap-gate field-effect transistor (FET) arrays with a gate length of just 50 nm. Moreover, the vertical wrap-gate formation is made by metal evaporation, thereby enabling further scaling of the gate length.
Producing transistors using InAs is a nontrivial task, but the researchers were able to accomplish this by exploiting nanotechnology concepts. They made the material self-organised according to a bottom-up principle instead of the conventional ‘carving-out’ method.
Besides enabling smaller transistor sizes and therefore smaller electronic gadgets, another significant advantage made possible by this energy efficient transistor is that batteries in mobile phones and portable computers can last longer and need not be recharged so often. In addition, this research work makes it easier to develop transistors that can communicate at higher frequencies, especially in the 60 GHz band.
Lars-Erik Wernersson, professor of solid state physics at the faculty of engineering, Lund University, and one of the researchers, says that their transistor model can pave the way for communicating in frequencies that are too high for today’s technology. This development will open up new doors in the realm of personal area networks (PANs), where communication is required for short distances such as between televisions and projectors, and similar home entertainment devices.
Stockholm-based Swedish Foundation for Strategic Research, partial sponsors of this research work, are going to provide additional funding to develop new wireless circuits using the newly developed transistor technology. The transistor has been developed in collaboration with a Lund University spin-off company, QuNano, based in Lund, Sweden.
For more information contact Patrick Cairns, Frost & Sullivan, +27 (0)21 680 3274, [email protected]
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