The history of the application of semiconductors for controlling
currents goes back all the way to 1926, in which Julius Lilienfeld led a
patent for a "Method and apparatus for controlling electric currents"
[1], which is considered the rst work on metal/semiconductor
eld-effect transistors. More well-known is the work of William Shockley,
John Bardeen and Walter Brattain in the 1940s [2, 3], after which the
development of semiconductor devices commenced. In 1958, independent
work from Jack Kilby and Robert Noyce ledto the invention of integrated
circuits. A few milestones in IC design are the rst monolithic
operational ampli er in 1963 (Fairchild?A702, Bob Widlar) and the rst o-
chip 4-bit microprocessor in 1971 (Intel 4004). Ever since the start of
the semiconductor history, integration plays an imp- tant role: starting
from single devices, ICs with basic functions were developed (e. g.
opamps, logic gates), followed by ICs that integrate larger parts of a
s- tem (e. g. microprocessors, radio tuners, audio ampli ers). Following
this trend of system integration, this eventually leads to the
integration of analog and d- ital components in one chip, resulting in
mixed-signal ICs: digital components are required because signal
processing is preferably done in the digital - main; analog components
are required because physical signals are analog by nature. Mixed-signal
ICs are already widespread in many applications (e. g. - dio, video);
for the future, it is expected that this trend will continue, leading to
a larger scale of integration.
