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Architects of a nanoworld behind the screens
27 November 2013
Twente, University of
New types of building blocks for electronics will be the future, that is clear for Nauta as well. “It is already possible to give a molecule the functionality of a transistor. But compare that to the huge complexity of current chips, with eight or nine ‘highways’ above each other, connecting all elements. How to reach this using these new molecules? There’s still a huge gap there. Silicon research and industry has shown an immense effort, that’s still going on for some time.” He stresses that current chips like microprocessors already contain billions of transistor with sizes in the nanometer domain. Microelectronics had become nanoelectronics already. “They are so small, around 22 nanometer, that you can count the individual atoms.”
Not self-evident at all
In his lecture ‘The invisible circuit’, Nauta asks his audience to imagine a world without chips. “If we wouldn’t have chips in our daily life, suddenly a lot of things like social media and internet, aren’t possible anymore. That would really mean ‘back to the fifties’.” That is: almost back to the time the very first transistor was invented, in 1947. Still, we take it for granted whenever there is a new generation of smartphones, tablets or other gadgets in the shops. “This is not self-evident at all. This requires top research and huge investments in new chip factories.” Nauta’s own group, one of the world’s leading groups in chip design, delivered several inventions that found their way to smart phones and TV’s. A well-known example is their noise-cancelling circuit that surprised the semiconductor world at first, but is a textbook example by now.
Nauta specializes in circuits translating the analogue outside world into the digital inside of the smartphone: the part of the circuitry taking care of transmitting and receiving, or ‘radio’. Complexity is growing rapidly there: with more and more mobile standards, a good quality has to be guaranteed with low noise, and if possible, using less energy. And all that on the tiniest possible silicon surface. “For each standard, you would need a separate filter. But that would take far too much surface. We now develop a filter that is tunable and can be integrated on-chip. That’s a development the whole world is looking at, because integration of conventional filters is almost impossible. Within five years, it will be commercially available.” This new type of filter would also be the candidate for new radio techniques employing every free part of the frequency spectrum, so-called cognitive radio.
Even if Moore’s Law, that predicts a doubling of the amount of components on every square millimeter of silicon every two years, comes to a halt due to physical limits, a creative designer still has years to go, according to Nauta. These physical limits have been pushed for decades now: as long as it is viable economically, industry will keep investing.