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How do you make a transistor?

5 March 2026

The magic behind the microchip

Have you ever wondered how a transistor—the fundamental building block of modern electronics—is actually made? It might surprise you to learn that these tiny powerhouses are crafted using light, acid, and an astonishing level of precision.

From sand to silicon wafer

It all begins with a simple disc of silicon—a fancy term for a purified bit of sand. This disc, known as a wafer, is then cleaned thoroughly. This wafer is the blank canvas on which billions of transistors will be created.

The art of photolithography: Tattooing logic gates

Next comes photolithography—a process that sounds complex, and it is! Imagine shining light through a patterned mask onto a photosensitive chemical layer on the wafer, much like developing a photograph. This process ‘hardens’ specific areas, creating a stencil for the next step. The unexposed parts are then etched away using acid—a process that’s as dramatic as it sounds!

Doping silicon: Turning sand into a semiconductor

What happens after etching? We ‘dope’ the silicon, which means introducing tiny impurities like boron or phosphorus. While they sound like magical potions, these elements transform ordinary silicon into a semiconductor—a material that can switch electricity on and off incredibly fast and at microscopic scales. 

Building layers upon layers

This process is repeated over and over, layering microscopic wiring and circuits until a fully functional integrated circuit emerges. These chips contain billions of transistors, each smaller than a virus particle, all working together to power your devices.

The full circle of transistor creation

Here’s the kicker: transistors are so tiny and complex that we actually need transistors—and computers—to build more transistors. The machines have quite literally unionised!

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