THE ELECTRONICS OF COMPUTERS 4 INTEGRATED CIRCUITS Answer these questions. a. Do you know how many transistors there are in a chip? b. What material are transistors made of? c. Do you know why fiber optics is much faster than other transmission media? copper: rame disposable: monouso to dope: drogare, trattare chimicamente fab: fabbrica to fill: riempire fingernail: unghia to mark out: delimitare to peel apart: aprire, sfogliare pezzo per pezzo pipe: tubo plant: impianto to be sliced: essere tagliato switch: interruttore, commutatore What is a bunny suit? Bunny suit is the slang phrase used to describe protective clothing that someone working in a clean room, i.e. a special room where microchips are produced, must wear to prevent dust and human skin or hair particles from entering the room s atmosphere. A bunny suit, worn by production line workers or technicians, is typically white and is made of separate pieces of clothing, including boots and hood. An integrated circuits (IC) or chip, is a tiny component, no bigger than a fingernail, which contains a huge amount, i.e. thousands, millions or even billions, of interconnected microelectronic devices to serve a specific function. The basic idea behind integrated circuits is to recreate a complete microscopic circuit on the surface of a piece of silicon. Electronic devices are built around a printed circuit board (PCB) which looks like an electric street map with all the electronic components, such as resistors and capacitors, in the place of buildings. Printed copper connections link them together like miniature metal streets. Although this structure is perfect for small appliances, computers require eight electronic switches to store a single byte, or character. As a consequence, the size of a computer electric plant would have been incredibly huge without the invention of the integrated circuit. The major uses of ICs are for computer microprocessors, mobile phones, digital computer memories, and other electronic devices such as timers and sensors. The process of making an integrated circuit starts with a raw chemical element such as silicon, which is chemically treated, or doped, to enable it to have different electrical properties. Then, a big single crystal of silicon is shaped like a long solid pipe which is sliced into thin disks as large as a CD, called wafers. The wafers are marked out into identical square or rectangular areas, each of which will make a single silicon chip. After that, the components are created by doping different areas on the silicon surface. The die, the small block on which the circuit is fabricated, represents the IC in its smallest possible form. To make it possible to connect the IC, we need a package to encapsulate the die. The IC package turns the delicate die into the black chip we are all familiar with. According to the way in which they are manufactured, integrated circuits can be classified as: monolithic circuits, monocrystalline, typically made of silicon hybrid circuits, which contain transistors, diods, and other components which are difficult to manufacture with monolithic technology, so the components are joined to a substrate or printed circuit board. Adapted from: www.webopedia.com 60 Module 2 FLOWCHARTING