Silicon Technologies in Brief

 

Most of us have heard of silicon in conjunction with high tech, but not many of us know what role it plays. A detailed discussion of the topics I’m going to cover would take too long, so we’ll just brush some basic ideas. In a nutshell, silicon is an element that can form a fairly unique crystaline structure. By changing this structure slightly, we can make silicon conduct electricity, or not conduct electricity. Being able to change the conductive property of the material is the reason we say crystaline silicon is a semiconductor; sometimes it conducts, sometimes it doesn’t (Pierret 1996).

Pure silicon, an element rarely found by itself in nature. Courtesy of Mineral.Galleries.Com © Amethyst Galleries Inc. 2008

Pure silicon, an element rarely found by itself in nature. Courtesy of Mineral.Galleries.Com © Amethyst Galleries Inc. 2008

What does this mean for high tech? Well, it all comes back to two things: that mysterious string of ones and zeros, and something called a transistor, which is made out of silicon. All high tech devices end up communicating in a digital machine language called binary. This language consists of just ones and zeros. All computer software and digital communication, at some point, is broken down into a binary code. Your probably familiar with the idea of all these ones and zeros bouncing around in your computer, but the same thing happens in your cell phone, GPS device, game console or any other digital device you might own.

 

 

The thing is, those ones and zeros really aren’t ones and zeros at all, they’re high and low potentials (voltages) in an electric circuit. There is a common analogy that compares water to electricity. If we follow this, electric current (measured in Amps) is analogous to water current, and electric potential (measured in volts) is analogous to the height of some stored water (like in a dam for instance). Using this analogy, a one is like storing up a bunch of water in a dam, and a zero is like letting all that water flow out until there is none left. If you want another one, just fill up the dam (high potential), if you want a zero, let it drain out(low potential) .

A transistor (which can be made of Silicon) is essentially a valve for electricity. In our water analogy, a transistor would be used to either let all of the water flow out of a dam, or close off the dam to let it fill back up. A transistor is often used like this as an on off switch, deciding between a potential high or low, a one or a zero. When Bell laboratories patented the Bipolar Junction Transistor in the 1940’s, it opened up the flood gates for an expolsion of progressivly smaller and smaller semiconductor devices. With the creation of integrated circuits (IC’s), many transistors could be cheaply grown on a single piece of silicon, along with other electrical components. This allowed for the design of whole electrical circuits made microscopic, effecient, and cheap (Jaeger 2002).

A silicon wafer with many hundred microchips on it. Courtesy of Lexikon's History of Computing Encyclopedia on CD ROM ©

A silicon wafer with many hundred microchips on it. Courtesy of Lexikon's History of Computing Encyclopedia on CD Rom © Lexikon's History 2002

 

 So, in the early 80’s, we had these magic devices that let us do all sorts of great things; and these devices were getting smaller. Gordon Moore, one of the founders of Intel commented that the number of transistors and other devices that can be placed on an IC would double every two years. This statement has come to be known as Moore’s law. If you’re not familiar with Moore’s law, then you’re at least familiar with the phenomena of electronics getting twice as small, half as expensive, able to hold twice as much infomation etc. about every two years (Pierret 1996).

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