Linked by fran on Tue 23rd Nov 2010 22:26 UTC
Hardware, Embedded Systems The CPU industy is working on 16nm chips to debut by around 2013, but how much smaller can it go? According to the smart guys, not much smaller, stating that at 11nm they hit a problem relating to a 'quanting tunneling' phenomena. So what's next? Yes, they can still add core after core, but this might reach a plato by around 2020. AMD's CTO predicts the 'core wars' will subside by 2020 (there seems to be life left in adding cores as Intel demonstrated a few days ago, the feasibility of a 1000 core processor.) A Silicon.com feature discusses some potential technologies that can enhance or supersede silicon.
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RE[5]: quantum tunneling
by ndrw on Wed 24th Nov 2010 13:35 UTC in reply to "RE[4]: quantum tunneling"
ndrw
Member since:
2009-06-30

Actually the whole progress (although not as fast as Moore's law predicts) continues due to decreasing transistor sizes and some system level techniques like integration, supply voltage gating etc.

Moore's law additionally dictates that speed of single transistors should grow and their power consumption should fall but that has not been possible since 130~90nm nodes (~7 years ago) and only small amount of progress has been made since then.

This limit has nothing to do with minimum sizes or quantum effects - it's simply due to the fact that we are no longer able to decrease the supply voltage due to the physics of transistors themselves. Transconductance of MOS transistors (in subthreshold range) is at around decade/100mV (and will never be better than decade/60mV of BJTs).

So if you want to have 5 decades span between Ion and Ioff currents (first for high switching speed, second for low leakage), a 0.25V margin to compensate for process variability and another 0.25V for putting the transistor in saturation&linear ranges (for Ion) you'll wind that you need a gate driving voltage (and thus supply voltage) of around 1V. There is no way to decrease this voltage without cutting corners, that is compromising on either switching speed or leakage power.

Development in last 5 years was heading in the direction of higher quantity rather than quality. Making 2x faster CPU costs 8x more power? Well, let's just make 2 CPUs, and flood them with cache memory, add whatever peripheries on chip we can think of, etc. That's not as good as the Moore's law but it is still pushing things forward.

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