electronics (IC, or "chip") A microelectronic
transistors and other components. ICs are constructed
("fabricated") on a small rectangle (a "die") cut from a
Silicon (or for special applications, Sapphire) wafer. This
is known as the "substrate". Different areas of the substrate
are "doped" with other elements to make them either "p-type"
or "n-type" and polysilicon or aluminium tracks are etched in
one to three layers deposited over the surface. The die is
then connected into a package using gold wires which are
welded to "pads", usually found around the edge of the die.
Integrated circuits can be classified into analogue, digital
and hybrid (both analogue and digital on the same chip).
Digital integrated circuits can contain anything from one to
square millimeters. The small size of these circuits allows
high speed, low power dissipation, and reduced manufacturing
cost compared with board-level integration.
The first integrated circuits contained only a few
circuits containing transistors numbered in the tens. Later,
Medium Scale Integration (
MSI) contained hundreds of
transistors. Further development lead to Large Scale
Integration (
LSI) (thousands), and VLSI (hundreds of
thousands and beyond). In 1986 the first one
megabyte RAMwas introduced which contained more than one million
transistors.
LSI circuits began to be produced in large quantities around
1970 for computer main memories and pocket calculators. For
the first time it became possible to fabricate a
CPU or even
whole uncut wafers as components.
[Where and when was the term "chip" introduced?]
(1997-07-03)