Aluminium encyclopaedia

Electronics

Aluminium is used for a wide variety of applications in electronics thanks to its properties - above all its good conductivity for electricity and heat, its low density, its non-magnetisability and the ease with which it can be processed.

In integrated circuits, so-called chips, which link millions of components on semiconductor platelets (mostly made of silicon) the size of a finger nail, conductor tracks made of unalloyed aluminium or aluminium alloys provide the connections between the components. These conductor tracks are made by etching vapour-deposited layers 0.5 to 50 thousandths of a millimetre thick in bands as narrow as 0.2 thousandths of a millimetre. "Refined aluminium" with a particularly low uranium or thorium content is used for the finest tracks because the alpha radiation resulting from these elements, which are present as traces in all metals, can cause damaging discharges. Aluminium is also increasingly replacing gold for the connections of the chips to the outside, as so-called "bonding wire".

Housings and mounting plates are made from aluminium as are heat sinks in the form of finned profiles to dissipate the heat from chips and power semiconductors, which are very much larger semiconductors used as switching elements in power engineering.

In optical storage discs (for example compact discs or CDs, optical video discs), the data track is vapour-deposited aluminium and in rewritable storage discs the magnetic layers carrying the data are applied to high-grade aluminium discs.

In high frequency engineering, transmitting and receiving aerials in the shape of parabolic dishes are mostly made from aluminium, as are shielding, coaxial cable and tubular conductors.