A microchip pioneer s prediction has a bit more life left in it
Apr 18th 2015 | From the print edition
NEWS of the death of Moore s law has always been greatly exaggerated. People
started to pronounce it deceased not long after Gordon Moore, co-founder of
Intel, a chipmaker, published on April 19th 1965 a paper arguing that the
number of transistors that can be etched on a given surface area of silicon
would double every year. In a later paper he corrected his forecast to every
two years, which has come to be stated as his law . Regularly proving sceptics
wrong, however, the exponential growth kept going (see chart), driving the
digital revolution.
Yet signs are multiplying that half a century later, the law is running out of
steam. It is not so much that physical limits are getting in the way even
though producing transistors only 14 nanometres (billionths of a metre) wide,
the current state of the art can be quite tricky. Intel says that it can keep
the law going for at least another ten years, eventually slimming its
transistors down to 5nm, about the thickness of a cell membrane. Other than
shrinking circuitry further, it has also started to stack components, in effect
building 3D chips.
If Moore s law has started to flag, it is mainly because of economics. As
originally stated by Mr Moore, it was not just about reducing the size of
transistors, but also lowering their price. And a few years ago, when
transistors 28nm wide were the state of the art, chipmakers found their design
and manufacturing costs beginning to rise sharply. New fabs (semiconductor
fabrication plants) now cost more than $6 billion. In other words: transistors
can be shrunk further, but they are now getting more expensive.
Makers of smartphones and other mobile devices will no doubt be keen for
chipmakers to keep on packing ever more computing and storage power onto tiny
slivers of silicon, and may even be prepared to accept their cost going up.
But compactness is less important for another fast-growing branch of the
information-technology business, cloud computing. In cloud-service providers
cavernous data centres, space is not at a premium, the way it is inside the
latest iPhone. What increasingly matters most to cloud providers is energy
efficiency: how much power their racks of servers consume, and how they can
keep them sufficiently cool to ensure that their chips do not fry. Fortunately,
one of the corollaries of Moore s law is that the energy efficiency of
transistors follows the same exponential law, doubling around every two years.
And like the law itself, it s not quite dead yet.
From the print edition: Business