The article outlined what became known as Moore's Law, the observation that the number of transistors--tiny on/off switches that churn out electrical signals that get represented as 1s and 0s--on a chip can be doubled in a short period of time. Adopted as a yardstick by the tech industry, the concept is one of the reasons the industry evolved into a high-growth, but high-risk, affair.
This FAQ explains the impact and consequences of the principles set down in the April 19, 1965, article.
What is Moore's Law?
When writing the article, Moore noted that the number of devices (which
then included transistors and resistors) inside chips was doubling
every year, largely because engineers could shrink the size of
transistors. That meant that the performance and capabilities of
semiconductors was growing exponentially and would continue to. In
1975, Moore amended the law to state that the number of transistors
doubled about every 24 months.
When the paper first came out, chips sported about 60 distinct devices. By contrast, Intel's latest Itanium chip comes with 1.7 billion silicon transistors.
As monumental as the article has become, it wasn't a big deal then. It started on page 114 of the magazine.
"It wasn't something you expected to join the archives," Moore said in a recent gathering with reporters. "I didn't think it would be especially accurate."
Why is it possible?
It's the miracle of industrial
chemistry. Silicon is a good semiconductor (which means it can conduct
electricity, but in a manner that can be controlled), and the
crystalline structure remains intact despite shrinkage.
Is the law now dead?
No, though various analysts and executives have incorrectly predicted its demise.
It will, however, likely begin to slow down to a three-year cycle in
the next decade and require companies to adopt alternative
technologies.
Some people, such as Stan Williams and Phil Kuekes of HP Labs, say the ability to shrink transistors will start to become problematic by around 2010. That should prompt manufacturers to adopt alternatives, such as HP's crossbar switches, to control electrical signals.
Others, such as Intel's director of technology strategy, Paolo Gargini, paint a more gradual picture. Around 2015, they say, manufacturers will start to move toward hybrid chips, which combine elements of traditional transistors with newfangled technology such as nanowires. A full conversion to new types of chips may not occur until the 2020s.
From a theoretical point of view, silicon transistors could continue to be shrunk until about the 4-nanometer manufacturing generation, which could appear about 2023. At that point, the source and the drain, which are separated by the transistor gate and gate oxide, will be so close that electrons will drift over on their own. When that happens, transistors will lose their reliability, because it will be impossible to control the flow of electrons and hence the creation of 1s and 0s.
(The nanometer measurement refers to the average feature size on a chip. A nanometer is a billionth of a meter. Current chips are made on a 90-nanometer process, while experimental devices about 6 nanometers long have been produced.)
What happens then?
Hard to say. If alternatives to silicon
transistors never materialize, Moore's Law stops. If alternatives
emerge, progress could accelerate under similar principles.
What's the best alternative?
Who knows? Carbon nanotube transistors, silicon nanowire transistors, molecular crossbars, phase change materials and spintronics are mostly now lab experiments.
Silicon, though, won't go easy. Manufacturers and designers love it. Chances are, silicon will continue to be incorporated into these new devices in some fashion.
"I view (silicon) technology as a fundamental way for bringing out complex microstructures and materials," Moore said.
Who said what?
California Institute of Technology Professor Carver Mead was the one
who dubbed it Moore's Law, a lofty title Moore said he was too
embarrassed to utter himself for about 20 years. David House, a former
Intel executive, extrapolated that the doubling of transistors doubles
performance every 18 months. Actually, performance doubles more like
every 20 months. Moore emphatically says he never said 18 months for
anything.
The rule also doesn't apply to hard-drive densities or to the growth of other devices. "Moore's Law has come to be applied to anything that changes exponentially, and I am happy to take credit for it," Moore joked.
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