How is silicon used in computer chips

Silicon changed everything. Manufacturing transistors out of silicon allowed them to be made small enough to fit on a microchip, opening the gates to a rush of gadgets that have become smaller and smarter by the year. The pace of innovation was unprecedented.

Chips began to be miniaturised at such a steady rate it was as if the technology was following a law. Only now, when attempts to shrink transistors any smaller are bumping up against the limits of physics, has the pace of miniaturisation slowed. Early transistors could be seen with the naked eye. Now a tiny chip holds many billions of them. More than anything else, it is this exponential improvement in manufacturing that has driven the digital revolution.

But silicon, the element at the heart of this revolution is a surprisingly humble substance, and one of the most common on the planet.

A technology that has spread across the world is made from one of the most ubiquitous substances on it. The semiconductor business has also become one of the most interlinked in history, with raw materials coming from Japan and Mexico and chips made in the US and China. But that vast worldwide network can trace its origins to just a handful of very specific places.

High-end electronics require high-quality ingredients. The purest silicon is found in quartz rock and the purest quartz in the world comes from a quarry near Spruce Pine in North Carolina, US. Millions of the digital devices around the world — perhaps even the phone in your hand or the laptop in front of you — carry a piece of this small North Carolina town inside them. The rocks around Spruce Pine are unique.

High in silica, a silicon-containing compound, and low in contaminates, the region has been mined for centuries for gemstones and mica, a silicate used in paint. But the unearthed quartz was discarded. Then came the rise of the semiconductor industry in the s and quartz turned into white gold.

Rocks extracted from the ground with machines and explosives are put into a crusher, which spits out quartz gravel. This then goes to a processing plant, where the quartz is ground down to a fine sand. Water and chemicals are added to separate the silicon from other minerals.

After that? There might finally be no choice but to abandon silicon for something less abundant and easy to work — good news for processing speeds, but almost certainly bad news for your wallet. It means that the core structural molecules that make up our bodies proteins, amino acids, nucleic acids, fatty acids, and more are built on skeletons of carbon atoms.

Tetravalency is a powerful basis for building molecules that are both strong and geometrically complex, and that duo of chemical virtues has allowed the evolution of all life currently known in the universe. Yet, if we know how the Periodic Table is organized, we know that elements in a vertical column have similar chemical properties — and right below carbon, is silicon.

This is why science fiction authors have spent so much time and ink of the idea of silicon-based life; being tetravalent itself, silicon is the most plausible alternate structural element in totally novel forms of life. Silicon is also happy to bond powerfully to other silicon atoms just like carbon to carbon and can thus double-lock certain conformations into place.

Both are presumed to be crucial to allowing the development of life. Of course, with silicon being so much more abundant on Earth than carbon, there has to be a reason that we are organic carbon-based , rather than silicon-based — and that reason comes back to the Periodic Table.

Without going into too much detail, elements that are vertically lower on the Periodic Table have heavier nuclei and larger electron shells; silicon is physically larger and heavier than carbon, making it less well-suited to super-fine tasks like, for instance, recombinant DNA. Chips today may have multiple cores. Silicon, the principal ingredient in beach sand, is a natural semiconductor and the most abundant element on Earth except for oxygen.

To make wafers, silicon is purified, melted, and cooled to form an ingot, which is then sliced into discs called wafers. A chip is a complex device that forms the brains of every computing device.

While chips look flat, they are three-dimensional structures and may include as many as 30 layers of complex circuitry. Chips are fabricated in batches of wafers in clean rooms that are thousands of times cleaner than hospital operating rooms. Fab technicians wear special suits, nicknamed bunny suits, designed to keep contaminants such as lint and hair off the wafers during chip manufacturing. Design specifications that include chip size, number of transistors, testing, and production factors are used to create schematics—symbolic representations of the transistors and interconnections that control the flow of electricity though a chip.

Designers then make stencil-like patterns, called masks, of each layer. Silicon is highly reliable and enhances certain aspects when using it in CPUs. Another reason that makes it the chosen is its resistance to high temperatures. Because resistance is a key factor when choosing a material for the base of transistors.

Conductors have low resistance and pass electrical current more easily, while insulators have high resistance and can block the flowing current. Silicon has semiconductor characteristics. This means, it does not always conduct electricity; It only does so under certain conditions, while under others it acts as an insulator: that is why it is known as a semiconductor.

These characteristics can be modified through a process known as doping, which is nothing but adding some impurities to the silicon to make it more or less conductive as required. Thanks to this, that allows building the transistors according to their electrical needs.

This quality of silicon makes it the most important element in the production of our processors. In CPUs, it is important that electricity should not be transmitted so easily through the transistors. Because, for a transistor, which must be able to turn it on and off at all times , it is necessary to have a semiconductor, a substance with a resistance that lies between that of a conductor and that of an insulator. Any computing device, either a computer or smartphone, operates in a binary number system.

That is, all operations are recorded, calculated, and displayed in a sequence of zeros and ones. A transistor in a processor can be thought of as a kind of switch. If the current passes through it, this is 1, if not, then it is 0. And there are billions of such switches in modern processors. A different sequence of zeros and ones forms information — programs, music, pictures, videos, and even this text. In the previous generation of computers , vacuum tubes played the role of transistors in the computers.