The tiny, mighty transistor

Saswato R. Das writes about physics and astronomy.

A little electronic device that triggered one of the most dramatic technological explosions in history turns 60 on Sunday. The humble transistor and its descendant, the semiconductor chip, which made the digital revolution possible, today touch nearly every facet of our lives.

All around us, billions upon billions of transistors are quietly at work in computers, cellphones, radios, TVs, printers, copiers, CD players, cars -- in anything with electronics in it. Transistors enabled space exploration and the personal computer revolution. (In the words of Bill Gates, “Without the invention of the transistor, I’m quite sure that the PC would not exist as we know it today.”) Without transistors there would be no iPod or hand-held cellphone. No Internet. There would be no multibillion-dollar semiconductor industry, no Intel, Nokia, Microsoft or Google. No Silicon Valley.

Today, the most complex silicon chips can carry more than 1 billion transistors each -- and we manufacture billions of new chips each year. It’s nearly impossible to comprehend the numbers. Each year we manufacture about 10 million times as many transistors as there are estimated stars in the Milky Way.

A transistor is a little electronic switch capable of amplifying electric current, invented by John Bardeen, Walter Brattain and William Shockley at Bell Labs in New Jersey on Dec. 16, 1947. They jury-rigged the first transistor using a paper clip, some germanium and gold foil, and found that it boosted electrical current a hundredfold. They kept the discovery to themselves for a bit, and showed their bosses the device just before Christmas. Bardeen, Brattain and Shockley won the Nobel Prize for physics in 1956.

Modern electronics had started in 1906 when Lee de Forest discovered that an electrified mesh placed between two electrodes in a vacuum could amplify electrical current and act as a switch. The resulting vacuum tubes soon became the workhorse of electronics, used in radios and the telephone system. By the end of World War I, Western Electric was manufacturing 1 million vacuum tubes a year.


Vacuum tube technology peaked with the construction of the first digital computer, ENIAC, built between 1944 and 1946 at the University of Pennsylvania. ENIAC was a colossal machine -- roughly 100 feet long, 10 feet high and 3 feet deep -- comprising some 100,000 parts, including 18,000 vacuum tubes. Lore has it that when ENIAC was turned on, the lights in western Philadelphia dimmed. A tube would fail every few days and would have to be replaced. That was the downside of vacuum tubes; they consumed an immense amount of power and failed often.

Bell Labs researchers had foreseen this problem and, in the mid-1940s, created a team to find a replacement. The goal was to make a solid-state device that would have no vacuum, no filaments and no moving parts. The team bet on semiconductors -- materials such as silicon and germanium that conduct electricity under certain conditions. By December 1947, the researchers had struck gold.

The first commercial product to use transistors was the hearing aid, made in 1952. Fortune magazine declared 1953 the “Year of the Transistor,” and, by 1954, Texas Instruments had introduced the transistor radio. In 1958, Jack Kilby at Texas Instruments built the first integrated circuit, which combined a number of transistors on a silicon chip -- another milestone in semiconductor history.

From those relatively modest beginnings sprung changes comparable to the Industrial Revolution. Many have already heard of Moore’s law, which has become a mantra of the Digital Age. First put forward by Intel co-founder Gordon Moore in the 1960s, it says that the number of transistors on a chip (and hence its processing power) doubles every two years, while the price of the chip falls by half. For more than four decades Moore’s law has held, driving incredible technological growth and miniaturization and wealth.

Today, a state-of-the-art chip contains more than 1 billion transistors packed into an area the size of a human fingernail.

To put it in economic terms, if the price of an automobile had kept pace with the price drop of a transistor, we would be paying less for a car than for a slice of pizza.

In the next few years, the question is whether the semiconductor industry can sustain this relentless progress. Further shrinking transistors is proving problematic as certain fundamental physical barriers are being reached. At the same time, new frontiers are opening up. The quest is on to create efficient transistors that use and boost light instead of electricity, which will enable much faster processing speeds.

So on its 60th birthday, answer your cellphone, boot up your computer, flip on your iPod -- and in the process, toast the incredible transistor, the humble electronic switch that, in two human generations, has forever changed how we live, work and play.