Micron is marking our 40th anniversary on October 5, 2018. As part of this milestone celebration, we wanted to share our perspectives on the Metamorphosis of an Industry. We hope you enjoy our three-part blog series, looking back at the history of memory and the fantastic, foundational changes we’ve been a part of during the last half century.
Moore’s Law and Dennard Scaling
The effect that Moore’s law has had on the electronics industry cannot be overstated. The idea that the number of transistors in a dense integrated circuit doubles approximately every two years was advanced in a paper written by Gordon E. Moore in 1965 and was validated over the course of the next half a century. The law has been used in the semiconductor industry to guide long-term planning and to set targets for research and development.
The capabilities of many digital electronic devices are strongly linked to Moore's law: quality-adjusted microprocessor prices, memory capacity, sensors and even the number and size of pixels in digital cameras. All of these have improved at roughly the same exponential rates and have dramatically enhanced the impact of digital electronics in nearly every segment of the world economy: leading to significant improvements in product functionality, performance, and cost on a regular basis and opening the door for many different companies to enter the market.
Dennard scaling relates to Moore's law by claiming that the performance per watt of computing grows exponentially at roughly the same rate. Dennard scaling, also known as MOSFET scaling, is based on a 1974 paper co-authored by Robert H. Dennard, a researcher at IBM. Dennard Scaling postulated that as transistors get smaller their power density stays constant, so that the power use stays in proportion with area. This allowed CPU manufacturers to raise clock frequencies from one generation to the next without significantly increasing overall circuit power consumption.
While Moore’s Law held true for more than 50 years, eventually it became more difficult to exploit its advantages. At the same time, Dennard’s Scaling appeared to break down in the 2005-2006-time period. The inability to operate within the same power envelope led the CPU industry’s transition to multicore architectures, creating significant challenges for memory technology. With each passing generation, the number of memory controllers per core decreased and the burden on the memory system grew.
Even with the end of Dennard Scaling and the slowing of Moore’s law—customer expectations continued to grow. For more than four decades, consumers targeted by the high-tech industry were conditioned to expect frequent advancements in product performance and capability. The memory industry was compelled to find new ways to improve system performance – exploring and developing architectures that process information in new and exciting ways.