1941

Doped Silicon

John Robert Woodyard (1904–1981)

If we had to pick a substance that engineers have used to impart the biggest effect on humanity, what might that substance be? Maybe it is gunpowder, which engineers use in guns, cannons, and bombs. By killing untold millions of people, gunpowder has certainly had an effect, although not a particularly happy one. Maybe it is uranium, which engineers use in both nuclear bombs and nuclear power plants. Or asphalt, which billions of people use every day for transportation, or the concrete used in so many structures. What about gasoline, powering most of our vehicles?

The award for the most influential material might best go to … drumroll please … doped silicon. Doped silicon was developed by physicist John Robert Woodyard while in the service of the Sperry Gyroscope Company in 1941. This material, the foundation of the transistor, has transformed our society in a thousand different ways. Look around you and count how many objects use computers in one form or another. Think about how much time you spend using a laptop, tablet, or smart phone. Think about the billions of computers connected to the Internet.

And think about where we are headed. The “Internet of things” is the next big thing. It is predicted that, in just a decade or two, there will be 100 trillion objects connected on the Internet. They will be everywhere: home appliances, cameras, sensors, cars, tracking devices, drones, our homes and their security systems. Doped silicon has made computers so inexpensive, so power-efficient, and so intelligent, that computers are embedding in everything and connecting together on the Internet. And then there are robots, which will be arriving in massive numbers in the not-too-distant future.

The doping process is conceptually simple. Start with a pure silicon crystal. Add various dopants, like boron to create an area of holes, or phosphorous to create an area with free electrons. Combining these doped areas properly, an engineer can create diodes and transistors. With transistors, engineers can create amplifiers, receivers, and computers. Our computer and electronics industries are built on top of doped silicon.

SEE ALSO Concrete (1400 BCE), Asphalt (625 BCE), Wamsutta Oil Refinery (1861), AK-47 (1947), Transistor (1947), Cluster Munition (1965), Microprocessor (1971), HDTV (1996).

A silicon wafer, pictured here, is a thin slice of semiconductor material.