Seventy-five years is a long time. So much so that most of us don’t remember a time before the transistor, a ubiquitous element in any modern electronic device. The transistor would never have become so useful and ubiquitous if the semiconductor industry hadn’t managed to make it small and cheap.
The most obvious change in transistor technology in the last 75 years has been the quantity we can manufacture. Reducing the size of the device has been a huge and successful effort, but the size is not the only feature that engineers have been improving.
In 1947, there was only one transistor. According to TechInsight forecasts, the semiconductor industry is on track to produce nearly 2 billion trillion (10²¹) devices this year. This is more transistors than were cumulatively manufactured in all years prior to 2017. Behind this barely conceivable figure is the continuing decline in the price of a transistor, as engineers have learned to fit more and more of them onto the same area of silicon.
The density of transistors in logic circuits has multiplied by more than 600,000 since 1971. To reduce the size of transistors, it is necessary to use shorter wavelengths, such as extreme ultraviolet, and other lithography techniques to reduce the space between transistor gates and between metal interconnects.
In the future, what counts is the third dimension, in which the transistors will be built on top of each other. This trend is over a decade old in flash memory, but it’s still the future of logic.
