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What Are Silicon Chips?

Silicon is a hard, glassy element. A silicon chip is a miniaturized circuit etched onto a thin wafer of pure silicon. Silicon chips can contain hundreds of millions of components per square millimeter. As well as being far smaller, silicon chips are much cheaper to produce than circuits made up of discrete components. They outperform ordinary circuits in speed and power consumption. Silicon chips are also called microchips, integrated circuits, ICs or chips.

Silicon
- After oxygen, silicon is the most abundant element on Earth. It is used to make integrated circuits because it is a natural semiconductor -- a material whose conductivity is somewhere between that of an insulator and a conductor. This property is necessary to make the diodes, transistors and other components that make up an integrated circuit. To be usable for chips, the silicon is processed till it is 99.9999 percent pure.
Silicon Wafers
- The purified silicon is melted down and large crystals of silicon are pulled from the molten bath. This is done in a laboratory so that the silicon can be kept completely free of impurities. Even a little dust or dirt in the air could ruin the product. The silicon crystals naturally assume a cylindrical shape as they grow. These cylinders are sliced into circular wafers. The surfaces of the wafers are polished to a microscopic degree of smoothness.
Photolithography
- A chip is built up in several layers. The circuit is etched onto the smooth surface of the silicon wafer using a technique called photolithography. Certain areas are marked to be "doped" -- to have intentional impurities introduced to change the number of electrons in the material -- while other areas will have metal or polysilicon tracks deposited on them. Large numbers of chips can be etched onto a single wafer. The wafer is cut up into individual chips.
Packages
- Once completed the chip is housed inside a package which protects the fragile silicon and allows it to be connected to an electronic circuit. Packages are made from tough, durable plastic with several metal connectors -- often called legs -- extending from the sides. These connectors may be soldered into place in a circuit or plugged into sockets in a circuit board. They allow electrical signals to flow to and from the chip.
Silicon Chip Use
- Silicon chips are used in all manner of electronic devices from pocket calculators to computers. They allow electronic equipment to be made much smaller than would otherwise be possible and dramatically reduce power consumption. The silicon chip is the foundation of modern computer technology.

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