Moore's law is a term used to refer to the observation made by the late Gordon Moore in 1965 that the number of transistors in a dense integrated circuit (IC) doubles about every two years.
Moore’s law isn’t really a law in the legal sense or even a proven theory in the scientific sense (such as E = mc2). Rather, it was an observation by the late Gordon Moore in 1965 while he was working at Fairchild Semiconductor: the number of transistors on a microchip (as they were called in 1965) doubled about every year.
Moore went on to co-found Intel Corporation and his observation became the driving force behind the semiconductor technology revolution at Intel and elsewhere.
Moore’s law is based on empirical observations made by Moore. The doubling every year of the number of transistors on a microchip was extrapolated from observed data.
Over time, the details of Moore’s law were amended to better reflect actual growth of transistor density. The doubling interval was first increased to two years and then decreased to about 18 months. The exponential nature of Moore’s law continued, however, creating decades of significant opportunity for the semiconductor industry. The true exponential nature of Moore’s law is illustrated by the figure below.
A straight-line plot of the logarithm of a function indicates an exponential growth of that function. The figure is courtesy of Intel Corporation, see Moore's Law (Intel.com).
Moore originally published the observations that would come to be known as Moore’s law in a 1965 article for Electronics Magazine, while he was working for Fairchild Semiconductor. An original draft of that article can be seen here.
As described by the Computer History Museum in Mountain View, California, the term “Moore’s law” was coined by Carver Mead, a professor at the California Institute of Technology (Caltech) in Pasadena, California, around 1975. Mead currently holds the position of Gordon and Betty Moore Professor Emeritus of Engineering and Applied Science at Caltech. Professor Mead has taught at Caltech for over 40 years. His early work paved the way for advanced semiconductor designs that benefited from the predications of Moore’s law.
Semiconductor process technology has always increased in complexity. This phenomenon has been the “innovation engine” that fuels Moore’s law. In recent times, complexity increases have been accelerating. Transistors are now three-dimensional devices that exhibit counter-intuitive behaviors. The extremely small feature size of advanced process technologies has required multiple exposures (multi-patterning) to accurately reproduce these features on a silicon wafer. This has added substantial complexity to the design process.
All this complexity has essentially “slowed down” Moore’s law. Moving to a new process node is still an option, but the extreme complexity and cost of doing so has slowed the pace of migration. Furthermore, each new process node is now delivering less dramatic results in terms of density, performance, and power reduction. The evolution of semiconductor process technology is reaching molecular limits, and this is slowing the exponential benefits of Moore’s law.
The slowing of Moore’s law has prompted many to ask, “Is Moore’s law finally ending?" This, in fact, is not occurring. While Moore’s law is still delivering exponential improvements, the results are being achieved at a slower pace. However, the pace of technology innovation is NOT slowing down. Rather, the explosion of hyperconnectivity, big data, and artificial intelligence applications has increased the pace of innovation and the need for “Moore’s law-style” improvements in delivered technology.
For many years, scale complexity drove Moore’s law and the semiconductor industry’s exponential technology growth. As the ability to scale a single chip slows, the industry is finding other methods of innovation to maintain exponential growth, ensuring that technological advancements continue to progress and meet the demands of the future.
