2.1 THE ELECTRONICS OF COMPUTERS INTEGRATED CIRCUITS The interior of a computer is made of a set of electronic circuits, called integrated circuits, built on a single small flat piece of semiconductor material, usually silicon. The integration increases speed and reduces costs if compared to the building of discrete, i.e. separate, electronic components. What is an IC? An (IC) or , is a tiny , no bigger than a , which contains a huge amount, i.e. thousands, millions or even billions, of interconnected microelectronic devices to serve a specific function. integrated circuit 1 chip 1 component fingernail 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 (PCB) which looks like an electric street map with all the electronic components, such as resistors and capacitors, in the place of buildings. Printed connections link them together like miniature metal streets. Although this structure is perfect for small appliances, computers require eight electronic to store a single byte, or character. As a consequence, the size of a computer electric would have been huge without the invention of the integrated circuit. printed circuit board 2 copper switches plant Uses of ICs The major uses of ICs are for computer microprocessors, mobile phones, digital computer memories, and other electronic devices such as timers and sensors. How to make ICs The process of making an integrated circuit starts with a raw chemical element such as silicon, which is chemically treated, or , to enable it to have different electrical properties. Then, a big single crystal of silicon is shaped like a long solid which is into thin disks as large as a CD, called wafers. The wafers are 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 , the small block on which the circuit is fabricated, represents the IC in its smallest possible form. To make the connection of the IC possible, a package is used to encapsulate the die. The IC package turns the delicate die into the black chip we are all familiar with. 2 doped pipe sliced marked out die Types of integrated circuits According to the way in which they are manufactured, integrated circuits can be classified as: , monocrystalline, typically made of silicon; monolithic circuits , which contain transistors, diodes, and other components which are difficult to manufacture with monolithic technology, and which are therefore joined to a substrate or printed circuit board. hybrid circuits MORE The integrated circuit was invented in 1958 by Jack Kilby and Robert Noyce who came up with the idea independently and fought furiously for the rights to the invention. 1 DO How big is an integrated circuit? 1 MORE A PCB is essentially a board that connects electronic components. 2 DO Watch this silent video and see how IC, or chips, are made: Posted by Intel 2 From Sand to Silicon: The Making of a Chip