The history of transistor

11 Aug 2024

(Image credit: me, saw this trend a few days ago so had to make one myself. Pookie Transistor XD)

I have a course on Analog Electronics this semester which seems interesting. The course more or less is all about transistors. I was reading a book Chip War: The Fight for the World’s Most Critical Technology by Chris Miller. Also Thanks to Asianometry youtube channel whose videos inspired me to write this blog. I’ll try to keep this article simple so that it can be understood by anyone who knows class 11-12th basic physics. Let’s begin.

The History

In the early days of humans various civilizations had their way to compute. Babylonians had abacus to play with large numbers, Indians had pāṭīgaṇita and dhuli-karma(dust-work). In the late 1800s and in the early 1900s humans saw an industrial revolution and they got a lot to compute. The offices used to have armies of human calculators occasionally equipped with mechanical calculator that could add, subtract, multiply, divide and calculate basic square roots.

Advent of electrical computers

In the USA they did The Math Tables Project in 1936 where they published 28 volumes of the results of complex functions, logarithms, exponential functions covering a total 201 pages. Specially the World War 2 increased the demand of computing. Slowly engineers shifted towards using electrical charges for computing. They started using vacuum tubes, conventionally a tube turned on was considered 1 and turned off was considered 0. Also an interesting fact is the vacuum tubes glowed like light bulbs attracting insects and engineers had to clean it, they called it “debugging”. So the word debugging got its origin from vacuum tubes.

William Shockley

A genius Nobel winner William Shockley born to a Mining Engineer in London, brought up in Palo Alto, California, went to Caltech for BS degree, did his PhD in Physics at MIT and then started working at Bell Labs in New Jersey in 1936. Yes the OG Bell Labs where C and Unix were also nourished. Shockley’s intuition was so good that one of his coworkers said as if he could actually see electrons flowing inside atoms.

Shockley specialized in Semiconductors. Semiconductors don’t conduct current when they are pure. But with some doping(adding Phosphorus or Aluminium impurities) and placing it in an electric field lets it carry current. Shockley initially had this idea to use this property of semiconductors as a switch representing on as 1 and off as 2.

In 1945 Shockley carried an experiment what he called a “Solid State Valve” and theorized using electric field as a “valve” to control flow of electrons though a semiconductor, but he struggled to build a working Prototype. Two years later in 1947 his colleagues Walter Brattain and John Bardeen(only person to win 2 Nobel Prizes in physics) took inspiration from Shockley’s theorizing and made a setup using germanium created the first point contact transistor proving Shockley’s theory right.

(William Shockley, Image credit: Computer History museum)

AT&T was in telephone business saw the potential of transistor’s amplifying signals that transmitted phone calls. It was also realized that they will be more useful in radio devices, hearing aids than less reliable vacuum tubes. Shockley became insecure about his colleagues who made a device that proved his theory and he was committed to outdoing them. He locked himself in a Chicago hotel room for two weeks over Christmas and began imagining different transistor structures. By January 1948 he conceptualized a new type of transistor made of 3 chunks of semiconductor material, the outer two chunks will have an excess of electrons while the sandwiched layer would have a deficit of electrons. And this is how the BJT(Bipolar Junction Transistor) was born.